I look at it this way: the Dodgers have the best potential but the most question marks. The Padres have the best ace (Jake Peavy) and best bullpen (Hoffman, Otsuka, Linebrink), but their offense and depth are not good. The Giants are getting pretty old and have a buttload of question marks themselves, but I look for Noah Lowry, Jesse Foppert and Jerome Williams to come up huge behind Schmidt and Tomko. Not only that, but they have Matt Cain, Merkin Valdez and Brad Hennessey on the way up. Even if they are old, they still have a talented defense; those 35+ year old knees in the outfield are a bit scary, though.
Still, I think the Dodgers are the most talented, but I think they're all going to get hurt. Both teams have excellent young talent on the way up, though.