I love Ichiro and Giambi, but in my opinion, neither has put themselves in a position where they were the obvious choice for MVP. This season you have three guys in the NL who would easily win the MVP in the AL: Bonds, Pujols, and Sheffield.
Sure Giambi has turned his season around, but April still happened. It still plays a large role in his 267 BA. Ichiro is a terrific leadoff man, but he just doesn't have the numbers across the board that ARod has, and neither does anyone else. Brett Boone could win it, and I happen to think that he has the best shot at this point, but I don't see him as more valuable than ARod.
I agree that ARod's a long shot, but I'd really like to see someone make a serious push for this award, and, in my mind, ARod is the only one currently doing it.
Honestly, I can only really think of five candidates at this point:
ARod, Boone, Ichiro, Giambi, and Delgado, maybe you could throw Maggs in for good measure as Kurkjian has done recently. In any case, someone will probably emerge, there's still 35 or so games to be played.