From personal experience, I'd definately go MB Quart. I'm sure there are other decent speakers out there, but I love those damn German acoustic engineers....
It might help to give a description of what kind of speakers you want and how much you want to spent.
OK, this was 100% a joke - I just read threads on CAF that are so vague that I thought this forum needed one of its own. I am by no means a car audio expert or even a novice, but man, some people pose some really vague questions over there. I guess I was feeling a little goofy today and found it funny.