I just upgraded my new 17" Intel iMac from the stock 512MB RAM to 2GB RAM (from OWC) and let me tell you it's day/night performance. This thing is much more responsive with the extra RAM. And right now my system is using a little over 1.5GB with only a couple apps running. I definitely would recommend upgrading to at least 1.5GB to appreciate the speed of these machines.
David
David