Hi Jared and welcome to FlyerTalk!

A big part of your research should be you first figuring out why you want to be in an airline frequent flyer program. And that's what they are, frequent flyer programs. Sure, it's possible to earn miles without ever flying, but there are better, cheaper, faster ways to get a "free" trip, if you're not flying at least a few times a year. Such as cash-back credit cards.

Are you saving for a big trip?

Are you flying fairly often but haven't been taking advantage of the programs?

Do you fly one airline or a mix of them?

If a mix of them, are they mostly in the same alliance? That means you only need one membership in each alliance. For example, Delta, Northwest, and Continental are partners in something called SkyTeam, which is an alliance of many other airlines. You only need to join one program, and then give that number to earn miles when you fly any of their partners. In fact, unless you fly well over 75,000 miles/year, it would be stupid to join more than one program in an alliance - because it is impossible to move miles between the partners, but you can fly any of the airlines with miles from any one of the programs. That's a common newbie mistake - spreading it around between two or three airlines so that you have nothing on 3 airlines instead of having a free ticket and elite status.

Do you have regular routes you need to fly for business?

Do you stay in hotels? If so, are you a member of a hotel frequent guest program? Which one?

So give us some more info to help you out. And put some info in your user profile so we know where you live (nearest airport that is), what programs you're already a member in, etc.