I'd do a little more shopping than what you have done, actually. Dick's Sporting Goods sells bicycles, but they're not a bicycle shop and their employees probably don't know a lot about bikes. I'd spend at least a little time in a bicycle shop and see what they have to offer (and if you find a bike that you like, buy it there, don't skeevy your way over to Dick's and see if you can get it on the cheap).