Tough to guess. The public doesnt really know THAT much about Nuts and Bolts yet, other than the fact its not going to be a traditional platformer... LBP on the other hand is a new IP, so it might be slow to get off the ground (of course, Assasin's Creed showed us that new IPs can do quite well if marketed correctly).
I think part of it could be decided by pricepoint of both games, too.
If i had to venture a guess, I'd say Banjo because it is an established franchise and developer. LBP looks great and all, and the User created content could absolutely make it, but I think that Rare may be doing something even more unique with the gameplay in N&B that will make it a hit. Ask me again after E3.







