I'm just about to order my MB Pro and plan on putting Vista on it as well (yes I know, plz don't hurt me ). Even though I only have 2MB of RAM right now, would it be better to go with Vista 64-bit for future proof, and is there any advantage to using 64-bit besides total RAM available. I don't want to buy XP, install it, then sometime down the road buy Vista and install again. I plan on getting an external HD for backup. Can I backup from both OSX Tiger as well as Vista?