Pettite could be excellent and should win lots of games because he plays for the Yankees, who probably have the best offense in baseball. But, he is extremely injury prone.
Lilly plays for an excellent team and behind Zito, Mulder and Hudson and that should be a huge boon. He seems to have powerful stuff, but seems to have trouble maximizing his pitch count. Only went 5.2 innings tonight, but got 10 K's. He has the potential to win 15+ games easily.
Lawrence has looked impressive so far and is a top 30 pitcher. However, he will have a hard time winning many games in San Diego.
Lohse has had something like three straight kicking outings and looks extremely good. The Twins are likely to challenge for the division title again, so I think he has an outside shot at 20 wins. He's a nice sleeper.
Pinero is a solid pitcher playing for another contending team and he should win 15+ games, with a decent ERA and WHIP.