What bike for newbie?
 

I plan on buying a bike mainly for exercise (mainly on my off days running) and intend to ride mostly on paved areas with a little offroad. I have found a GT Timberline in my price range (250 or less) and also a Trek 3700. I am new to this so I have no knowledge of wht to buy. All help appreciated.

For your applications, I think you generally have five different routes to go.

1. Hardtail MTB - usually has front suspension with around 3" of travel, big knobby 26" tyres and designed more for offroad rather than onroad riding but you can always "trim-down" the tyres to semi-slicks to make it more road-friendly. The position will be more upright than a roadbike but there are different kinds of hardtails. I would suggest one that's designed more for XC riding than say a hucking or freeride bike.
2. Comfort Bike - generally very upright seating, smaller to medium sized 26" tyres with less aggresive tread patterns and may sometimes be equipped with a low-travel (around 1") front suspension fork as well as possible a suspension seatpost. These are not meant to go very fast or far. They will generally not have higher gearing or as many gears as other bikes either. They're basically multispeed versions of the cruiser bikes. They can handle very light offroading if need be. Some of these are also billed as "utility bikes".
3. Hybrids - sport 700C wheels with medium width (for roadbikes) slick or semi-slick road tyres and will sometimes come with front suspension although I personally think that for this type of bike, suspension is unnecessary and would prefer a carbon or high-quality steel fork. Sometimes they will also have a suspension seatpost too although I personally would prefer a rigid carbon post. They will position you in a lower more roadlike position that's fairly close to that of a performance XC MTB. These bikes are more road oriented but if you pick clean lines through very light offroad trails, you should be okay.
4. Cyclocross - basically roadbikes designed for offroad course but not to an extent of a full-fledged MTB. They will have wider 700C wheels with more aggresive treads than a roadbike. They will position you in a lower roadbike-like manner and have drop handlebars as opposed to flat handlebars of the other above bike types. They're usually made of high-quality frame material and don't have suspension. Unfortunately, most of these bikes are priced higher as they fill a much more niche market.
5. Tourer - very much a roadbike with longer chainstays and longer wheelbase to make them more stable. All components are heavier duty but also means the bikes weigh more. They have many of the same attributes as a cyclocross bike except they also have provisions to mount racks and fenders. They also have lower and wider range gearing like a MTB. They're designed for carrying a lot of load over long distances. Some people find they make excellent commuters too.

My suggestion would be to go out and test ride models of each of these types of bikes. Then you can start narrowing down specific brands and models.

You might try a comfort bike. That's a bike with front shocks and a shock in the seatpost. It has wider tires and stronger rims and frame than a road bike (a racing 10-speed). So you can go on streets and go on unpaved paths with bumps in them.

My wife and I just started biking again after years off of it. She got a Giant Cypress, and I got a Specialized Crossroads. We've both been very happy with them and bicycle nearly every day, between 5 and 20 miles of paved and unpaved road at a time.

I've heard good things about the Trek, but never tried one.

I would suggest not getting a mountain bike unless you're really going off the roads. It's a lot more work to pedal these on the streets. Our comfort bikes work just fine both on the street and on rutted dirt paths. I'd stick with a hybrid or a comfort bike.

Bill

Did you ever think about a recumbent? Check them out. They are a blast and are oh so comfy.

'bent Brian

Since you are a runner do you think you might "branch out" to bi/tri-athlons? If so you might consider a road or tri or cross bike and ask the folks in the Triathlon forum what bikes they ride.

I got a cyclocross bike when I could not decide what I wanted. Nothing like having a bike that can do a little of everything when you need it to. It started life as a commuter/weekender & then graduated to duathlons & cyclocross racing (not that I am actually any good at either but very fun!). Check out the cyclocross forum as well.