Oh, no! Is it crap? I thought I might like to see this too! There's so many actors I can't stand, actually. But top of my list by a long way is Robin Williams. Then Tom Cruse. But I think that's because he's a nutter and a short arse.
<Added>Mark Kermode's review of Mama Mia has persuaded me to go and see it. Basically, everything about it's crap but the songs are so excellent that they make the movie a must see. And if Mark says that it's a must, then I'm going!