Hehe, bought the ram, literally takes 2 minutes to install in an iMac. After so many people bash the iMac for its un-upgradeability, it took me over an hour to put ram into my old HP media center because the ram slots were buried deeply behind tons of other stuff. Ridiculously simple. I can;t believe I actually have paid apple to do this in the past....$150 for an extra gig of ram...what a bad move.
Advice for future Mac buyers: add the ram yourself. It's really not as hard as you might think. For an iMac you need a regular-old screw driver and about 2 minutes of time!
BTW, going from 2-->3.3 GB shouldn't feel like a big difference, but my computer feels a lot snappier. My bet is that it's 80% psychological haha