I'm a big believer in Powe, and I'd like to retain him over BBD, if for no other reason, then we have Powe's bird rights and not BBDs. But BBD probably has more long term upside (both Powe and Davis have had games where they take over, remember BBD against Pistons where he seemed to score or go to the line everytime down the floor in the 4th quarter?) so if the team were comfortable with him, fine. BBD is also a better bet at Center IMO, which is a weakness in Powe's game when you have KG at PF and Perkins at C - the backup big needs to do the Center stuff that KG doesn't (or doesn't like to).
Don't know much about the GSW guy, but he looks like a solid option at both wing spots based on 82 games, is he much of a 3pt shooter?