GPU... IMO stay with ATI. I will never go with a Nvidia again, a few reasons...
*Every time you turn around AA or AF doesn't work in games until you go into the Nvidia controller and play with settings to make it work.
*There is always an update to new games you have to wait for. Yes, updates happen with ATI as well, but you never have to wait over 30 days for the "correct" update for that game (yes they miss it once in awhile, but still way better then Nvidia), I have seen Nvidia wait more then 30 days + and it took more then 1 update to get it right.
*Heat. IMO the cards burn way to hot for the speeds they are pushing. And when they get to hot, no warning (like video lag), they just shut down.
This is my 1st Nvidia card from the time I have been on computers (early 90s), lesson well taught, ATI is the way to go... Again this is just me, I'm sure others will disagree.
CPU... I am with AMD right now, next one will be an Intel... If for any reason, AMD isn't the side by side race anymore with Intel like it use to be 3 years ago at a better price... Intel is kicking now without sucking money from your pocket.