I just made that same upgrade. I went win 7 64x. I used windows 7 advisor to check my hardware for 64 compatibility. I then downloaded the appropriate drivers.
I chose to do a dual install. I have Win xp 32 on and win 7 64x on two different harddrives.
I found the upgrade to be painless. Took me about 10 man hours of install to get the rig up and running.
I had the intention of flipping back and forth (xp32 and win 7) but haven’t. I’ve booted into xp only once since this install 2 weeks ago.
Of course, all of this was done in anticipation of cubase 6 which should be arriving in a few days.
go 64bit with windows. as for cubase 5.52, I use 64 bit flawlessly.
I haven’t had to use the bridge software (my main pieces are virus ti 64 bit 4.1.5, geist 64 bit, dcam works fine, stylus rmx is fine, kontakt player 4 runs fine, and dimension pro is fine)
The only plug that I havent installed is the reaktor player (which does not run well in 64 bit daw).