Hi, I'm just about to make the leap from windows to mac in the form of an iMac, but I'm not sure which one to go for. I've been to the Mac Store and both the 21.5 and the 27 inch screens have pro's and cons. I like the dimension of the 21.5 in terms of bulk on the desk, it's not too intrusive. Initially I thought the 27" oversized but when I actually sat in front of it the immersion seemed great, and I could imagine making use of all the screen real estate with tool bars, email, when editing video clips etc. So undecided on that, though I think I like the 27. In terms of specs, I would love to pay for the min specs, I've not got an awful lot of spare cash. Maybe if I tell you what I'll be using it for you can give me the benefit of your opinion and perhaps convince me one way or the other. Thing is, I presently have an i7, my wife an i5 and if anything it seems her system which cost a third of the price, runs better (at least for normal apps) so I'd like some honest opinions about the advantage of the i7 over the i5 or indeed the other way if that's what you think. I don't just want the i7 because it's best on paper, would there be a very clear difference? I will be using it predominantly for work (stage 6 architecture student) the programs I'm using are: AutoCAD 2011, PS, ID, SketchUp and I aim to start using Vectorworks Architect and will buy iWork instead of Office. I don't want to use windows at all so software will all be mac native (I will need to relearn AutoCAD on the mac I think)... From what I've seen on youtube, the 27" i5, 4GB RAM, 1 GB GFX seems to run really well, or do you think I would really benefit from upgrading gfx card to 2 gigs or the processor to i7? I will buy some crucial RAM later on and expand to 12GB myself. Or maybe you think the 21.5 inch would more suit my purpose, in which case is the 512MB GFX enough or is there a way to get 1GB on 21.5 inch? Whatever you think, please share with me so that I can make my decision well. I made such a bad decision with my last windows PC and I don't want to repeat the mistake!!! Thanks.