Really want a new Imac but still can't decide between the 21.5 & 27. Even a trip to my local Apple store has not given me a clear answer. I know the size and resolutions are different but what specifically would I be able to do on a 27" screen that I am not on a 21.5"? There weren't obvious differences when playing around in the store. However I believe the 27 is pretty much the best display Apple makes to date, even better then the 30"