Ahh... what compatibility issues?? I using 64bit W7 and itunes and I have NO problems. My iphone and shuffle syncs fine with it. There's a 64bit version of itunes you know.
And to Daniel Gray, W7 is definitely an improvement over Vista. If you can run Vista you should be able to run W7 just fine. If you want to use the 64bit version of W7, your processor has to be a 64bit for it to work, I've tried installing it on a 32bit processor laptop, doesn't let you install it at all.