This is a blowing your own horn posting, but the post does include some good links and information. If your thinking of moving to WIN 7 anytime soon, this would be a page you would want to keep handy.
I have been using WIN7 since it was released and have had no issues, runs fast with no issues with anything not working, though I also had VISTA from almost the beginning as well with little to no problems.
Great piece of information is that I run WIN7 on a Dual Core 1.8 with 2G and it’s great. One reason you might want to look at CDI off lease products as we have both Dual Core and Core 2 Duo off-lease products available.