Hello. I am looking to buy a late 2012 27in iMac. Should I go with the 2.9 i5 or the 3.2 i5 model? I don't really do much editing. Just watch video. Is 512mb graphics in the 2.9 model enough? I am definitely getting the fusion drive on whatever I get. So would a base 2.9 model with the fusion drive be the best bet for me? I'd probably keep the computer 3-4 years. How future proof would that be?