Robbie Williams. I detest him. Talentless freak from a crap boyband, who has been talked up as a mega-star, believes his own hype and was given the most lucrative record deal ever. AND he then has the cheek to whinge about how depressed he gets. I'd put him out of his misery, by punching him 'til my hands fell off.
There are others, many of them mentioned above, but he stands out.