I thought I knew my way round them too but Windows 7 surprised me, I'd suggest leaving UAC on for a few days & see how you get on with it. The biggest problem I found with installing Poser with UAC switched on was having to wait up to 5 minutes for UAC to think about whether to let me install or not (could just be my machine though) & having to type in a password every time.

Ironic that I switched to Ubuntu that does exactly the same thing in asking for a password to do anything that might be a risk to the OS.

If you've got multiple users on the same machine then keeping UAC running would be a good idea.

Windows 7 64Bit
Poser Pro 2010 SR1