You guys don't need to be sarcastic jerks. You were new once too. That's what this board is about. Choosing the right regional is NOT an easy thing to do. You can go back and read 100 pages on any of the regionals' threads and get an equal mixture of: 1) Don't come here, it sucks, 2) I've had a great time here, it's fine if you live in base, 3) ALL regionals suck, go to whoever will upgrade you to captain the fastest, 4) Get a CJO to an AA WO who won't OBR or JM you and I know you don't know *** I'm talking about.
To the original poster: I agree with the guy(/girl) who said to figure out where you want to live, and check the "airline profiles" section to see who has a domicile there, and start there. If you're young and don't have a family and willing to move wherever they send you, then you can worry about other factors.
I also agree with the guys(girls) who said to take anything a recruiter says at a job fair with a grain of salt. Understand what their job is. They may be great guys, but they'd probably get fired if they told you the truth about any big reasons you should avoid their airline. Additionally, the more FOs that come to their airline, the more senior they get comparatively, and the better their lives are.
Skywest is the largest regional, with lots of growth and domiciles, and most people on this site tend to agree that it's a decent place to work, compared to the other regionals. However, they don't have the big first year/signing bonus which can be a LOT of money at some other places.
The American Airlines wholly owneds (Envoy, Piedmont, PSA I believe) have a "flow" program where you get a big leg up into American eventually. The flow is a long ways off though, and most folks feel you're a lot more likely to get hired outside of that "flow" before you ever reach that point, unless you have some nasty skeletons in your closet.
PSA has something called an SAP which basically means that after about a year there, your ability to adjust your schedule to your liking becomes much easier than at any other regional.
Most people on this site tend to feel that your number 1 priority should either be to live in base, or to upgrade as quickly as possible. Regardless of which you think is more important, it's going to take a lot of reading on this site, and posting in the individual airline threads, to feel like you have enough of a handle on the different airlines to make an informed decision.
Good luck.