Windows 7 is best.Because it has better features then the other.And Windows 7 is a vast improvement from Vista as it takes up much less ram and has other optimizations such as fast booting times. I recommend Windows 7, and if you really don't want vista and don't want to wait for the final version of Windows 7, you can download a copy of the Release Candidate from the Microsoft website for free and use it up till June of 2010. I am working with the Release Candidate right now and so far I have absolutely no complaints, considering Im a heavy computer use with advanced software.
