Oliver Coipel is doing House of M, and I agree, I like his style and art a lot.
Immonen's a good artist I think, he just has a couple different styles and is experimenting a bit with a more cartoony influence.
Jim Cheung's great, he's working on Young Avengers, I haven't been dissapointed by an issue of that yet, art or storywise.
Then there are the greats, like Ross, Kirby, etc. who needn't be mentioned.