Apples and Oranges....
64 Bit operating systems have more driver issues than 32 bit OSes, whether Vista or XP. If you definitely need a 64 bit OS, by all means go for it, but for most uses, for most people a 32 bit OS will suffice and give less issues.
No, I was referring to XP Pro, not any version of Vista. The Intel corporation has decided to skip Vista altogether and so have I. This is a long debate with no resolution in sight, but for the time being, XP is still faster than Vista, especially in gaming.
Give some serious thought about why you would need a 64 Bit OS, before you commit to one.