I've never seen House. I'm obviously missing something!
He is great in BlackAdder, and perfectly sweet in Stuart Little (as an American).
Not sure he's the best actor of all time, but he is there in the ranks of those who aren't just 'themselves' every performance. Colin Firth is one such - can be totally dashing Darcy, or rather plain cuckold (more than once). Daniel Day Lewis might top that list.
Or maybe VM - I was totally unaware of ever having seen him before until LOTR but realise now I must have done - so I must have only ever seen his characters not the actor.