So far, Symantec's corporate AV works fine (latest and greatest, put out just for Vista, checks in with the standard console without problems), Nero's latest version (I believe it's 22.214.171.124?), Adobe Acrobat 7.0.9 works (even the printing feature, though the 64bit versions still don't). Alldata 9.0 works, MS Money works, I use SlySoft's Virtual CloneDrive for mounting images without issue. PSPWare works fine... you get the idea. Up to this point, the only things I've come across that don't work:
Nero's image mounting functions - no big loss
VPN clients, such as CheckPoint's SecuRemote
That's about it at this point.