I need to get riding again, and the new job has showers, lockers, and bike storage. I need to bring back and forth my laptop, lunch, the essentials for clothes change, and stuff I haven't thought of. I don't have a bike that with rack eyelets, so I'm curious your thoughts on backpag vs rack. I'm in SoCal, so weather is not an issue.

Rear rack and panniers for me. I transport too much stuff for a backpack every work day, plus I've had back and neck problems in the past (although it's been years now) and want to avoid any possibility of that. If you go with a rack and panniers, there are lots of options. I went with Ortlieb backroller classics, which are expensive but excellent. Good luck, and good riding....

Rack. I can't stand having anything but a shirt against my back in hot weather.

I wanted to start this exact thread earlier today! Okay, I usually use Ortlieb panniers but it's kind of a PITA to load it up with whatever I need each time and attach it to the rack, then ride wherever I'm going, unload it and carry the pannier awkwardly all day. Panniers are great when I have huge, unexpected loads like groceries or laundry but that's not that often and I think the weight of the rack affects the ride too much. I just don't carry enough on a daily basis to justify having a 3 pound rack attached at all times. So I bought an Ortlieb Tracker 35L which expands to a pretty huge size and I'm gonna take off the rack, so I can carry the backpack easily with me when I need to carry a lot of things or leave it at home and enjoy a more lively ride. So both are good but panniers really shine when you have a huge load to carry. For my daily needs, a backpack with the ability to carry a lot more will do.

If you have paved surfaces, have a decent distance between stops, and minimal walking around off the bike once you get to your destination... I'd opt for pannier(s). However, if your route includes some singletrack, you are making several stops that are relatively close together or had to do some considerable amount of walking while keeping your bag(s) with you... backpack.

In truth, there is no right or wrong answer here. You will get all kinds of responses, whether it be panniers, backpack, mess bag, expanding trunk bag, folding baskets, Carradice type saddle bags, or even an odd nod to the all mighty milk crate.

I personally have hit upon the solution of using a backpack along with one or both of my old Nashbar Townie grocery panniers. Backpack can be shoved into the pannier for comfort or worn for maximum cargo capacity. The panniers fold up when not needed so that they aren't catching wind and a u-lock can be stuffed into one when folded, but they aren't the easiest to mount/remove (compared to Arkel and Ortlieb).

Rack and panniers for sure. (I've done both.)

rack for me hands down. No more back pain, no more sweaty back

Rack with a dry bag bungied onto it. The dry bag has a shoulder strap so it's easy to take off the rack and carry. Guess a pannier with shoulder strap would work too...

+1 hate carrying anything on my back...

Not sure I appreciate you folks in SoCal reminding us that you have "no issues with weather" either!

backpack, small, 20L is more than enough.

can use the backpack for rock climbing and as a personal item (carry-on) when traveling.

a backpack is so much more versatile than rack/panniers.

if you're talking commuting only, rack/panniers may be better, but as part of an active lifestyle, a backpack is much, much better (just try rope-climbing with a pannier )

I like a rack with wald folding baskets and a bungee cargo net into which I throw my backpack. Not the most elegant looking of solutions, but it's like 10 seconds on each end, is super easy to carry the backpack to where I go changed and, if I decide to get groceries on the way home, the backpack can go on my back and the groceries can fill the baskets. Downsides, heavy, not particularly attractive. But, if you're using a dedicated commuter, it's not such a big deal.

I use a back pack. But my commute to work is only 4.8 miles, all my work clothes stay in my work locker along with my iPad. So I don't have to haul much weight. In your case, I'd do the rack deal. Don't much about them, never got the opportunity to mount one and use one. Good luck!

I prefer/use rack and panniers over rucksacks. Also, +1 for the wald baskets.

If you can live with the slightly wacked weight distribution, a rack, hands down.
I try all different things to keep me somewhat non-drippy in the summer months because
I use a backpack most of the time, and I have come to: a wet T-shirt placed in the freezer
for about 1/2 hour before my ride and a one of those freeze packs in the backpack itself.
My ride is only 4 miles in, so that works out pretty well

Oh man! I have so got to try that... 'cos it's the wackiest thing I've heard in a while

Rack and panniers. A backpack throws off my balance and makes my back sweat like crazy.

This.

I'm into front panniers on a rack, now.. those with a quick release , so I can pop, them off,
and bring them in.

the bags, they're paired together..

A rack with a Gym bag zip tied to it via a plastic insert to give some support on the inside. To stabilize the load a bunji. Works great and it can be folded compactly when not in use. Also weigh almost nothing.

I use a messenger bag or a small back pack for carrying personal items such as spare clothing, pump,spare tubes and tools and few other things. I would never leave any of these personal tems on my bike when I lock it outside. My bikes are also fitted with front and rear racks which I use for heavy bulky items and when doing grocery shopping. People who whine and complain about sweaty back from wearing backpacks are just exaggerating the problem and making it sound as if it's some great hardship or life threatning event. There are backpacks out there made especially for cycling such as Camelbacks and Deuter and they are very comfortable to wear.

Rack and tail bag. I only have the tail bag because my fiancee was embarrassed about the milk crate, though honestly it was sometimes more convenient.

Rack and panniers. Around town I like the Ortlieb Bike Shopper on one side and a pannier with laptop sleeve on the other side (Racktime Workit Pro or Orlieb Office or Downtowner).

Also, front rack at midpoint of fork is very nice for a basket and/or small panniers down low. Some bikes ride better with the weight on the front.

I also feel that backpacks offer more organization for small items which is a big plus IMO. Also I carry a lot of electronics like a MacBook Air, an external hard drive, a camera, a Kindle, etc and I never feel comfortable with those things in my panniers. The roads are way too rough around here. I use 700x38 tires, a steel frame and rack, and I unload when approaching a rough spot I can't avoid, but still I am not comfortable leaving electronics in a pannier like that. I think my muscles and bones offer more shock absorption and protection for my valued electronic gadgets. Also I didn't realize sweating was such a problem for so many people. I sweat, too but it's bearable.

Messenger bag in the winter.... Rack / Pannier in the summer. I find the pannier much easier to load, but to warm for the summer month.

Ok, so perhaps this better for another thread, but I'm at a crossroads on a commuter bike. I have lots of frames, but longer lots of budget. I have a full suspension MTB with knobbies for the dirt, Merckx for long rides, a carbon frame for the shorter rides when the group likes to hammer me, an two late 80's steel frames without rack eyelets that aren't built up (a Paramount and an RB-1.)

If I go the rack route, is there something study and stable that doesn't need eyelets? I ride all nicely paved roads, the commute will be about 12 miles each way, and if I damage the work laptop that would be bad. I'm concerned about the weight of stuff overwhelming a non-eyeletted rack.

You can use p-clamps to stand in for eyelets. Like so. https://www.rivbike.com/product-p/rh3.htm