Thanks for the suggestions thus far. esp. the links by teamonrun. Can you verify that they're under 25lb? I'd probably get a medium or perhaps even a small. I really like the "give" that the front suspension gives you when dropping curbs. And, an upright bike is the way to go esp. with all those cars around.

My commute is not that long: 4.5 miles (1 way).

As long as the bikes shifts smoothly, I don't really care about component quality. I have ridden cheap walmart bikes and those components won't work.