Definitely the Weasleys
After all, who wouldn't want a family like them? Bill and Molly are great characters, easy to get on with, apart from Molly's passive aggressive attitude towards Hermione, including getting her bad gifts, in one of the books, and her occasional sending howlers.
I'm not sure what I'd make of older brothers who were always playing practical jokes, but I think I'd get used to it, plus The Burrow just looks like a great place to live!