Windows 7 Ultimate and surely Genuine .....I loved Windows Professional XP also yet the Ultimate is best one
XP is good for some of my essential work related softwares. But Windows 7 is what i prefer on my home computer.
I like WIn 7, it is fast and all the functions are good and game explorer is awesome. Boot time is fast and i didn't experience any problem in win 7.
XP.service Pack 2 .All time best OS. Full time support and program compatability. I use lots of softwares and i tell you its very easy to run them on XP.