I would personally just get a bike through a bike shop, it's better than limiting your selection. I guess if you don't have the money, then go that route, but I would do a fair amount of test riding first. As many as you can.

As for REI, that place is like my toy store. I can always find something I want, mostly clothes. Just wander around, you'll be surprised at how many things you didn't realize you needed! My birthday is coming up in about a month, and all I've asked for is REI cards. I'm in the market for some new trekking poles for hiking and hopefully some more wool socks. I just bought new hiking boots last week, and my husband picked up some new cleats/pedals, along with arm warmers with a GC he had.