I miss my Macbook Pro and sort of regret giving it to my sister for law school. Since I was done with grad school, I really didn't use it much as I just used my desktop PC when I was in school and now that I have an iPad, I use that for light browsing, music listening and reading while in the couch. What I miss most was the trackpad. Though it's not available on the iMac, using other people's PC laptops is just wrong. Plus I simply miss iPhoto for my general photography (nothing on the PC compares) and iMovie is very nice. But that's another topic. Ok, so I'm in the market to sell my PC and parts that are worth more detached from the PC on eBay and using the funds to get an iMac. I know for my living space, I'm going to have to go with a 21.5 inch. But I can't decide on the $1100 with the 9400M GPU/500GB hard drive or the $1500 one with Radeon 4870 GPU/1TB hard drive. Hard drive is neglible since I can use external drives for my vast music and movie collection (they are internally on hard drives in my PC now). So my question is how much better is the ATI gpu over the Nvidia one?