Don't forget that there is a hybrid between shorts and bibs: shorts with suspenders (braces). Greg LeMond recommends using suspenders with shorts in his book. That's what I did before I could afford bibs. I still use them with my old shorts. KMart has some simple, sort of industrial suspenders that work great. And here is the hybrid advantage for the guys: you can detach the clips from the front for a standing pit stop.

Rich