I have to agree completely with barr08. I bought a 20 inch iMac w/ 2 GB RAM and it does everything I need to to do without any trouble. I run a ton of apps at the same time all the time. I use Photoshop on it and it really isn't bad and I know that it will be even faster once the software is Universal. I had a dual 1 Ghz G4 Powermac and was drawn to this when I upgraded cause with a scanner, printer, Wacom tablet, external drives, and everything else I hook into it, I need to conserve space where I can. The screen is nice and bright (actually I don't turn it all the way up cause it is too bright at highest level) and couldn't ask for a more beautiful picture. I don't think that there is a real need to go with the 23" display. Yeah, it is always great to have more screen but it isn't like you are going to be held back by a 20" screen. I am sure whatever you decide you will be happy but maybe by going with the iMac, you can spend the extra money you would save on other things you could use.

Also I don't think I would worry about the getting outdated real soon either, especially if you are someone who upgrades their systems every few years. I don't see there being anything I can't run for quite awhile with this machine.