I mentioned a while back that I was going to take back PES 2008 and get FIFA 08. Much as I didn't want to do this as I have been a Pro Evo guy for the past 8/9 or so years I did it. My observations...
FIFA 08 graphics are not as good as PES2008, I presume thats because the PC version does not contain the 'NEXT GEN' game engine that the PS3 and 360 version does... however they are still quite good.
Best thing about it though is that it has a 1440x900 resolution output and I can run the game on its maximum settings without any frame skipping whatsoever... this goes for online play also.
Online is an absolute dream to play.
Final verdict - Pains me to say but for the PC... FIFA 08 is the game to have.
I'm hoping to get a PS3 for christmas so I will get PES 2008 on there!! Also might check out the 'next gen' engine on FIFA 08 too