Yeah, and very annoying they are too.
Quite a few celebs do the voices for that Natural Fruit Confectionary Company, or whatever it's called - might have already been mentioned.
Stephen Merchant does Barclays. He has a very distinctive voice and I was surprised when I heard him on a banking advert.
EDIT: Didn't realise this was an old thread. In this very post, I nearly mentioned that Patrick Stewart used to voice over the Domestos adverts. Looking back, I already made the comment - over two years ago! What a sad life I lead...