Running windows 7 x64 bit professional here without a problem. I agree it has to be the best microsoft OS in a long time. I have 8 gig of ram and it sees it all. I was running Vista 32 bit and windows only saw a little over 3 gigs. Much better gaming results than with Vista 32. I did the upgrade to Win 7 x 64 and popped in a geforce 2 gig 560ti and I have not regretted it. I run ROF on all the highest settings and run low 40s to upper 50s fps. I guess I average around 50. And this is on an old Asus p5k deluxe with a Q9550 overclocked at 3.6. Cant wait to get my hands on COD, gogamer moved my date back to April 19th.

Win7 x64 clean install on a SSD is a must. I would not recommend an upgrade. And get a SSD disk, best thing that has happend to my computer. Put all your applications and games that you use the most on the SSD and the rest on a large HDD.

But if you have a large Steam folder then you need to think twice, Steam can only install to one disk.

64 bit home version limits you to 16 gig of ram. Pro limits you to 192 gig of ram. also microsoft support of home version ends in 2015 for pro it ends in 2020. Pro is only about 30 to 40 bucks more.

http://en.wikipedia.org/wiki/Windows_7_editions

There is a chart on this link that shows all the differences between versions. I have the professional 64 bit version and dont regret getting it over the home version at all.