Definitely Will!
Although I also like Alex Parks, G4, Lemar and used to like Kym, although her 15 mins are up IMO!
Girls Aloud have also been v. successful. I don't really like them, but their songs are too catchy and I always end up with them stuck in my head!!
The only one I don't like is Javine. If that's what you mean of course! (not Jamelia)