I'm a fan of Specialized because I think you get a lot of value for a great bike. Plus, Specialized offers nice accessories and has some great saddles available in 3 widths. With the '08's coming out in about a month or so, I'm seeing good prices on the '07's.

We have a local bike store that is good about taking trade-ins and we get a little discount for the upgrade. Maybe you can find a dealer that is willing to work with you on saving $$ for a gently used bike.