Well I installed Windows 7 Pro x64... finally.
Last night I put in a new motherboard and added a 9600GT for Physx. I had to rewire my case for about 3 hours to get it all to fit.
I kept getting blue screens during the install and it turns out one of my sticks of memory is bad. After swapping out my DDR2-1066 with some decent DDR2-800 I had laying around it installed without a hitch. Its an upgrade version but it activated just fine without any previous installation.
So far I have to say I'm impressed. It looks a lot more polished than Vista and a few of the things I missed from Vista have actually been replaced with some much more convenient features. For example, there isn't a quick launch any more, and I've been using quicklaunch for my drive shortcuts for years. Instead I just added a "Computer" toolbar to my task bar and now it will display any drives on my computer, including any removable drives that I add. This is much more convenient.
Also, the start menu is awesome now. I like the "pin to start menu" and "pin to taskbar" features. It seems like they've gotten rid of a few things that always caused problems too (creating new folders in the start menu and moving things was always problematic... now you have to do it through explorer).
Another thing... my hard drive isn't grinding away constantly like it always did right after installing vista. I don't know if that was related to indexing or background defragging but it was always pretty annoying seeing my hard drive activity light going crazy when I wasn't doing anything.
Oh and the new Microsoft Security Essentials seems great. I don't know how well it detects viruses but the program is only like 5Mb to download and it installs in less than a minute. Its really light and compact. I don't think I'm going to bother with any other antivirus software.