I've been reading a lot on this forum lately and have decided to post finally.
I just moved to the South Bay (Campbell, CA) area and find that with all of the bike lanes and relatively short distance (7-8 miles each way) to work, I should be commuting by bike.
I've also been taking into account the health advantages (I'm 195 and 5' 9", which is a bit too much).

Anyhow, I sold my bike before I moved out here and am now looking to start commuting the 7-8 mi. to work. Any advice on a bike that would be versatile for the area? I've been thinking mountain bike, but wasn't sure if someone would be able to lend a hand in recommending something that I would be better off starting with.
I'm not looking to go overboard on a bike initially, but I don't want a crap bike from the start either.

I think I'll probably want to get a pannier to carry my laptop and clothes. Luckily, they have showers and bike lockers at work.

I'm also not sure how extreme I'm starting out, is 7-8 mi. each way too ambitious for just starting? I figure even at 7 mph, it'd only be an hour to get there and over time it will/should get better/faster.

Any help is much appreciated. Thanks!

Look at the "Advice for New Commuters" sticky at the top of this section. Unless you plan on also riding on rocks and mud, a bike with thinner tires (32-35 mm) and no suspension will give easier pedalling. 8 miles each way will be nice once you are in shape, but it may be a good plan to only do it 2 or 3 days a week when you start. Budget for spending money on spare tubes, basic tools, water bottle and lights. Good luck!

Yay! What a sensible decision!

I'd say don't go for a mountain bike, unless you're planning to also go off-roading on it in a big way. The knobby tires and suspension will slow you way down (although you could put slicks on it and lock out the suspension... it will still be heavy). Being slow isn't much fun; you get way hotter, and go slower, and interacting with faster traffic becomes that much more challenging.

A cyclocross bike can be both rugged and fast, and makes a great city bike. A road/touring bike can also work out just fine, especially with some wider tires (at least 28x700C would be my recommendation). Hybrid and fitness bikes also make nice rugged city bikes, and can have a more upright seating position and wider range of gearing than those other styles, which you may find is more comfortable and better suited to steeper hills/slower speeds.

Pannier is a great idea to keep your back cool. I'd also highly recommend fenders, a helmet mirror, and at least one water bottle and cage for hot days. 7-8mi could be walked if you have a mechanical issue, but at minimun, a tire patch kit/spare tube, levers, and means of inflation would also be a good thing to keep on you at all times. Practice changing your tube before you find yourself roadside racing the clock with a flat. Alternatively, I think there are some 'goo' products that seal small punctures as they happen. Your LBS should be able to help you out with all the accesories. I like having a floor pump at home so that keeping my tires inflated is more convenient.

7-8mi is do-able for a new commuter, but give yourself lots of time at first, and try doing a couple similar (or shorter) rides on the weekends to try it out. You can start working on your fitness right away by doing a little walking/jogging a few times a week (even 20-30 minutes at a slow pace), and that will help make the transition to biking even smooother. It might also help if for the first couple weeks you only bike commute 2 or 3 times a week, or park the car at the halfway point for the day. Your first trip in might be great, but on the trip home your muscles could be pooched, and it will feel really hard. Then, the next day, they could be stiff and sore, and your butt will definitely be REALLY sore (although it won't hurt until you get on the bike, will get better in a few minutes, and will eventually not hurt at all... that takes about a week). Your body will adapt quickly, and then you can let the good times roll! 7-8 mi is a nice distance to bike. If you stick with it, you're guaranteed to be fitter and stronger. Eventually, you can probably expect to do the trip in about 30 minutes or less, depending on how often you have to stop.

Another thing to consider is how sure you are that you're committed to riding. If it's an experiment and you're not sure if it will stick, you might be better off spending less money to get a used bike or an entry-level new bike for maybe $300. If you decide you like it then in a year or two you can upgrade to something nicer and keep the old bike as a beater/emergency/loaner bike.

On the other hand, if you're really, really sure you're going to commit to this, it may make more sense to spend money to get a nicer bike up-front.

A "hybrid" is probably a good choice. A lot of companies are now making dedicated urban and commuter bikes that would be good to look at. 700x32 (wheel diameter and tire width, in millimeters) or 700x35 tires will probably be best, but if you start with fatter tires (700x37 or 700x40) it's easy enough to buy narrower tires and tubes later.

I third the "hybrid" bicycle for what you describe. Try looking for wheels that are listed as having 36 spokes because 195lb + gear + pothole is tough on wheels.

withfoam

I recently moved here (I live in downtown San Jose), and I commute to work which is in Santa Clara - 9 miles each way. I am 5'10" and was north of 200lbs when I had a heart attack at age 44. I knew that it would only be a matter of time before I stopped going to the gym, but it is relatively easy to ride the bike to/from work each day. Cardiologist tells me that I am in great shape now, and I have dropped 30 lbs. My cardiac event was 8 years ago, and I feel far better today than I did then.

My average speed varies from 12mph to 18mph depending on how hard I want to work. Most often I do 18mph on the way in, then shower and get dressed at work, then keep my work clothes on, and do a leisurely pedal home.

Where do you work?

Some hybrid models are fairly upright. If you're going for hybrid look for a model that gets you leaned over a bit more over the bike. Otherwise 8 miles + wind may really wind you!

Kona Dew is pretty reasonable hybrid that's not too upright, I use it to commute on. You might also want something with drop bars depending on your preferences - it would be good to try out a few different styles of bikes at a shop.

Hard tail mountain bike off of craigslist. Get it tuned up, throw on an inexpensive rack, some smooth tires, and some fenders and you are good to go. Or just get a kona smoke.

You can commute on anything. However, some bikes lend themselves to going fast, working up a sweat, etc., just by the very nature of their design and intended purpose. Roadbikes and tourers have similar seating positions and encourage you to step it up and work up a sweat. Mtbs are heavier and you end up working up a sweat. Upright hybrids and Dutch style commuters remind you that you cant' go too fast w/o really working at it so you might as well just relax, take it easy and enjoy the ride. And you'll probably end up sweating less because you'll be moving slower.

For a cheap new bike, check out the Kona Africa bikes. Single and 3-speed uprights designed to haul. They're not built for speed, but they'll handle your commute fine. Of course, if you want speed, check out road, touring and cyclocross bikes.

The number one tip to remember is: don't get frustrated. You may not be able to do the whole 14-16 mi RT right off the bat so get a bike, do some riding after work and on the weekends and build up to that distance. Pack some tools and water w/ you on your rides. When you can do the distance comfortably, start riding different routes to work to get that figured out. Stick w/ it and good luck.

I started bikeing 7 month ago for my 14 mile commute each way. I bought a Montague folding bike and drove my car 9 miles and biked 5 miles for 2 month. I then tried parking my car 5 miles in and biking 9 miles. I found I could only do it 2 days a week and the other 3 days I did 5 miles. It will definitly take a while to build up. I wind up getting an Trek FX+ which now allows me to do the entire 14 miles and is great on windy days. Getting a Trek FX bike would definitly help you have a fast and smooth commute.

https://www.trekbikes.com/us/en/bikes/road/fx/72fx/

I started a similar length commute a year ago, and just plunged in, riding every day. After a week of being beaten to death by my mountain bike, I bought a Raleigh Detour. Broke spokes constantly (I'm 6'6" and weigh 220#) until I found a great used rear wheel that solved that problem. I'm about to order a custom sized, steel, road oriented frame from Gunnar. Go with something that rides well, and that means more road/touring oriented than a mountain bike. It will be easier for you (that helps with motivation!) as you get in shape riding slow, and will let you ride fast once you are in shape, which will take a couple of months or so. Pick something that fits you, that has bullet-proof wheels, and get heavy duty tubes. Broken spokes and flats are frustrating and demotivating as you are getting started, so avoid them!

What's your budget?

Very limited? Vintage road frame with rack/fender mounts. <300
Somewhat limited? Used bike off craigslist. <400
Not so limited? Used bike from the LBS, or a ~500 dollar new hybridish bike.
Skies the limit? Cyclocross/touring bike, start around $800, can cost $4000+.

Sort out what features you want, drop bars are far more comfortable then flat, and depending on riding position can help decrease wind resistance (most important for speed.)
Most commuters want/need rack/fender mounts, ability to fit 32-38C tires AND fenders, durability over weight, and gearing appropriate for the terrain. Ride a few bikes that match your short list, spend 15-30 mins on each bike to see how your neck, hands, and back feel.

Saddles always hurt on new bikes, it can get expensive finding the right one, budget for that. Avoid lots of padding, sounds like it's good, but it causes a lot of pain unless you're tooling around for 2-3 miles tops.

Oh, unless your bike is locked inside a secure building, keep it cheap, nice bikes tend not to last very long locked up outside.

I like Touring or Cyclocross bikes myself for what you mentioned. However expect to pay around $1k for them. Otherwise if you are kind of familiar with bikes and strapped for cash then browse your local Craigslist or see if a LBS has used. For 7-8 miles the multiple hand positions might come in handy as well.

I just did a quick search and found some used on craigs list. I don't know if they are the right size or type, all I'm saying is keep an eye out.

https://sfbay.craigslist.org/sby/bik/1597696080.html

https://sfbay.craigslist.org/sby/bik/1597256179.html

https://sfbay.craigslist.org/sby/bik/1597146836.html