Tight now I'm o 2 64 bit systems and 1 32bit
the first one are a 2008 server and a vista ultimate (not yet sp1).
both of them run smooth and very well, stable and no issues.
The major advantage, as pointed out, is that on 64bit systems you must (if you do not diable it) use signed drivers.
That means that the overall quality of the driver is higher, positive side, but some small hw devices or old ones will not have the driver, due to the costs associated to the signature. And this is the negative side.
Said that I had to give up my hauppauge for this reason...
but I'm anyway very very very happy of both server and vista.
In addition to that if you want to use 4GB of ram (as I do) the 64bit is mandatory.
As a general perception when I moved from the 32 to 64 on exactly the same hw I had the feeling it was slightly more responsive. I do not have any data to support this, just an inpression.
It even must be said that as of today very few programs are compiled for x64 and very very few are DESIGNED for x64.
Thus the real advantages (if any, but I think they could exist) still have to be explited.
Mf