Without more detail on the BSOD's it could be hardware in which case the choice of OS would have little bearing.
Have you tested your hardware components to eliminate them from the equation?
Personally, I'm sticking with XP for a while, Vista 64bit is slowly maturing as an OS but I'm still dubious because of the price (Vista Ultimate). XP SP3 will be out soon though it is basically just a roll up of all the post SP2 hotfixes so nothing major to be had there.
It's only a couple of years (if Microsoft release on time - 2010) until we will see Windows 7 and i think I may stay with XP until then, to mind Vista just reeks too much of Windows ME (affectionately known as Microsofts Error) for me to change.
To qualify my above position, I have run (dual booted with XP) legit copies of Vista Beta2, RC1 RC2 and RTM so I have had hands on experience with Vista.