Billups is much better than Bibby. I like Bibby alot but Billups, as Piksi pointed out, plays All-NBA D. Bibby plays all-nba worst D next to Nash. Offensively, Billups is still better. Billups DOESN'T miss 4th quarter FTs like Bibby does (although Bibby is about as clutch as Billups other than FTs. Billups does have better teammates, but Billups is also a great find that we could have had if we so desired (FA), although I think he's been molded from a shoot first, to a more combo-ish, pg. Billups, like Bibby, was a great college PG (both were top 3 picks) although Billups had more trouble finding his nitch (6 teams).
Honestly, great D isn't a common place for PGs, on that list, the only guy's who play D well are Kidd (better in the past) and Billups. Terry isn't a bad defender, but did anyone watch the playoffs last year. Paul, I haven't seen enough of him to judge yet, but from looking at his stats, and the talent he's surrounded with and to be in the playoffs this year is just amazing. Nash is great, he shoots AWESOME, he doesn't play D, but that shouldn't be required for a great PG. He passes, and he passes the best in the league, but honestly, he's the only awesome passer I think we have left in the league. Brevin isn't bad, well actually he's pretty good. But, I'm not sure if his skill sets will transfer (I'm pretty sure we could get him for a fair price if the Kings desired since they have Felton).
Davis, I've always liked Davis and I'm not sure if he can be blamed for all of GS problems, but he is a CHUCKER, a HORRID shooter (fG% wise). He does play decent D but he's never been too consistant. Miller is more of a combo guard, and plays the 2 with the little man on the court (some reason can't remember his name). Mike James has never been proven to be a starting PG in the nba. Yes he's having 1 great year with Toronto, but then again it's Toronto.
If we could get Billups, Nash, Paul or Kidd for Bibby and whatever, I'd do it, otherwise were stuck with a pretty damn good PG who doesn't play D. As others have said, it's easy to blame the system. The system doesn't require him to be a great assist man. If he did pass like he did in Vancouver, the system wouldn't be running.