Ah, I know there's been many threads about iMac decisions, but I've yet to find many w/this particular concern. I've pretty much decided that, yes, I want an iMac. I'm coming from a Powerbook G4 12" (which breaks my heart to give up, but alas, it must be done). But I'm still debating between the 17" vs the 20." The 17" has all the features I want except for the graphics upgradability. However, based off of all the research I have done on this, it seems most people say the 20" is better anyways. Is the 20" very different in terms of portability? Say, if I want to move from one flat to another across town, how much worse off am I? Also, is the graphics card on the 20" w/256mb noticably different than the 128mb one on the 17"? (After all, there is more screen on the 20" the graphics card has to work for so I had been figuring it may not be too big a difference). I want to play games like Civ4, Sims2 and I also am going to be using aperture with raw format from a D70s.