I have no problem developing on a Windows 7 system. (Don't know how it is under a 64-bit version of it to be honest)
The only downside is that the IDE is slow. But you can fix that really quick when you go to the compatibily tab of the VB6.exe and check the "Disable desktop composition".
And the problem with the UAC can also be fixed. See my thread http://www.vbforums.com/showthread.p...ues&highlight=