I was so apprehensive about windows 7 that I actually dual-booted it off my xp machine, but fortunately I've grown to like it and haven't booted back into xp in years. DX 10 has a lot of nice features, though they are largely around shaders and surfaces. My favorite one though has to be dynamic wet surfaces. When I first played Call of Juarez, the town level where it was raining and you had to do a quickdraw gunfight the rain was dripping off my character's hat and clothes and it just sold the whole thing for me.