Difficult one this, for me anyway. Because you're really saying that the movie is good enough to override your dislike of the actor.
I also cannot stand Jim Carey... but 'Man In The Moon' is excellent and- - as much as it pains me to say - Carey was....mumble mumble...ok. But then I have always liked Andy Kaufman so the movie was bound to at least interest me.
Can I nominate Nicole Kidman? She annoys me in most films I've ever seen her in, and I really cannot understabd the accolades she gets (I know delzegg would mention 'Moulin Rouge' but having never seen it, I could not comment.) However, I have to begrudgingly admit to liking her performance in 'To Die For'.