Hello Mac'ers, I have been needing to buy a new computer for awhile but have been holding out for the refresh. Today is a happy day! I have a set amount of money to spend on a new purchase, so both of the 27' versions are out for me. I don't understand very much about computer architecture and processing, and I want to make sure I make the right purchase. Can anyone explain in layman's terms the meaningful differences between the two 21' models? Besides the slight increase in processor speed and the bigger hard drive? I use the computer primarily for work (internet, word, processing) and for hobbyist film editing on final cut express. I also play a lot of World of Warcraft. Basically, I want the computer that is affordable, but do not want to buy the base 21' if the top 21' is considerably better for what I need. Will the base 21' become "obsolete" before the top model? Or would it be better for me to buy the base model with upgraded memory? Any insight would be greatly appreciated. Thanks!