Depends on you really. If you just want to play the game, then feel free to just get the XBLA re-release. If you want the original experience though, then go for the Nintendo 64 version. While the core game is the same regardless of which version you get, there are some differences between the two. For example, direct references to Nintendo have been removed in the XBLA version, but the scrapped Stop 'n' Swop feature between Banjo-Kazooie and Banjo-Tooie has been re-added in the XBLA version.