I'm slowly migrating over to 64 bit. My new Dell computer came with Windows 7-64 bit. Everything I throw at it seems to work very well. Everything is stable as is. In the next couple of months I may upgrade my SonarX1 Essentials which is a 32 bit application to Sonar X1
Studio which can be run with 64 bit. The same for East West Symphonic Orchestra program which is 32 bit now, but a 64 bit Play engine is available. So I may upgrade that as well....it's just a matter of getting the money together to buy the 64 bit software.
My Ivory II and Audition CS 5.5 are still 32 bit applications, but work well with W7-64 bit. I don't think 64 bit versions are available yet.
I have 8 gigs of memory on the way...