Chavez would definately be in contention if he didn't get hurt. He'd near 40 homeruns IMO.
That said, Ortiz, Manny, Sheff and Vlad are all close in my mind. I love Miggy and he's one of the reasons my fantasy team is in first place, but I have a hard time giving the award to a player who's team is horrible.
Manny and Ortiz have eachother, so I'm going to cancel them out.
Sheffield has less support than everyone thought he would at the beginning of the season. A-Rod not having a great year and the Giambi case. Yet A-Rod is still a great player and guys like Jeet, Posada, Matsui, etc. are all in the lineup so cross out Sheff.
That leaves Vlad. Injuries to Garrett Anderson, Troy Glaus, Darin Erstad, Tim Salmon, etc. have killed the Angels as well as horrible pitching from 'ace' Bartolo Colon. Vlad has carried that team and they have a real shot at the playoffs. If they make the postseason it's Vlad hands down in my mind. If they don't, whoever has the best stats out of Manny-Ortiz-Sheff will get it IMO.