Who is Dating John Mayer?

After a short lived romance with Jessica Simpson, it appears that he has moved onto another blonde - Cameron Diaz.  I have never really understood why women seem to swoon for this guy. He always looked a little shabby to me. Bleh.

Update:  John has since moved on to actress Jennifer Aniston. I am not exactly sure how stable this relationship is though, being that they have broken up and gotten back together a few times now.

Update 8/2010: John and Jennifer are no longer an item.  Who knows what this serial dater is up to now.