Well technically I'd say NSMBU even though I didn't really enjoy it. NSMB2 had just come out and even that let me down. For nostalgic reasons I'll vote for the first one (but it controls very weird compared to the newer ones). Also it has better level design and bosses.
Edit: I did love one thing about NSMBU, and that is NSLU! Also, I don't hate NSMBU, but it's way too much like NSMBWii. The unified world map is neat though, and so are the controls.
Yep.







