I'm looking to buy an iMac. I currently have been 2 weeks without a computer ,returned a rMBP I had previously bought as I think I prefer a desktop. Right now I'm existing on just my iPad, and it's been working out fine with the exception that I can't play the ocassional World of Warcraft on it. I need an iMac that can run WoW on fair/good settings 40fps, turned off shadows/water is all I require. Aside from that I mostly use a computer for browsing forums/email/surfing/twitter. I'm not sure which iMac to go with as I don't want to overbuy if it's not needed. I would prefer the 21" screen size. Any input?