After much deliberation between the iMac and Mac mini I feel I am falling into the iMac camp. Seems that a decent graphics card is a necessity to get the best from FCPX. My problem of course is which one would best suit my needs. I am a guitar tutor and need to upgrade from my 2007 white iMac 20 inch to a machine capable of running Logic Pro and FCPX. I want to create instructional videos for my students - nothing too flashy, but I would like to use some effects with graphical overlays and possibly use two cameras. I realize that I will need external storage etc. but I have a budget of around £1600 (UK pounds) for the iMac itself. I would be able to get a basic educational discount. The machines I have narrowed my search down to are: 21.5" with 3.1 GHz i7, 16GB RAM, 1 TB Fusion Drive, GT 650M graphics - £1,662.00 27" with 2.9 GHz i5, 8GB RAM, 1 TB Fusion Drive, GTX 660M graphics - £1,597.00 (I would upgrade the RAM with Crucial RAM) which would even the RAM stakes and also the price. Unfortunately the 27 inch i7 is beyond my budget. So, would it be better to go for the processing power of the 21.5 inch's i7 or the 27 inch with its weaker CPU but better graphics card and screen? My other considerations would be reliability and quiet running as I do audio recording in a fairly small room. Thanks for your thoughts.