Vista isn't bad and though I now use 7, I didn't upgrade by choice my laptop died and this came with 7 on it. Though the space hogging process of Vista (and 7 and XP for that matter) is a problem the best way to control it is to utilize a seperate smaller partition for the OS alone. The reason why is that then the system cannot spread over the other drives and must compare and delete irrelevant updates once new ones are applied and many other things that it just doesn't do if it isn't forced to.

7 looks better (so long as you tweak settings somewhat) but otherwise theres not much difference than vista apart from sometimes (excluding games) I have trouble getting programs to install because of reverse compatability.