I've been using Ubuntu for over 18 months, and it just gets better and better.
If windows works for you, great, but I've found Ubuntu can do everything my Windows XP system can do - but updates and software installation is so much easier; after you've got the operating system installed, you've got endless "repositories" of available software at the click of a mouse.
I still have Windows XP on my hard drive (so I can "dual-boot"), but I almost never use it these days. I'm converted!
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