My 1.5 ghz G4 is just not cutting it anymore,to slow. The Imac 27 is way to big for my desk. Will I be making a big mistake by getting 3.33 ghz c2d with 4gb by not waiting if they bump up the 21.5 with a I3 or I5 ? I know either way it's going to be a Huge improvement of what I'm using. Thx