What do you think about Keith Allen? He is the Sheriff of Nottingham in BBC's Robin Hood and plays a priveleged little git, but also a sneaky (yet clever) liar. Although, I should say "was the sheriff," as he announced in April he would not return for a 4th season, wanting to move onto other projects.
http://www.youtube.com/watch?v=aosG18gjCpI
That's kind of depressing, one of the reasons I watch the show is because his performance as the Sheriff is always enjoyable.