1. Windows 7 (Though my laptop don't support Aero)
2. Windows XP (Before Win7, the best OS Microsoft ever made
3. Mac OSX (Just love the look, feel and functions of it)
4. Ubuntu (The best with Linux is that everything is free
which is good if you are only 15 and don't have that much money. Like me)
All of these are very good. There is not much difference in between them
Sorry if you think that I wrote to much. I just had to.