AT&T Park(SBC/Pac-Bell) hands down. No matter where you sit you get great veiws of not only the park, but the bay. The only park that gets close to AT&T is PNC.
The worst park I have been to is Dodger Stadium, it is just like Madison Square Garden, its old and rundown. Now that I think about it, a rundown park is perfect for the Dodgers, because it is like them.
--Chris