I will order one as soon as they are available. My main "desktop" is currently a 1GHz iBook G4 sitting on an iCurve, with an Apple BT keyboard & mouse. 😉
But what is it with you guys "throwing out" your old computers and wanting to save the displays??? My goodness, I've still got a working Commodore PET 4032 (bought new ca. 1981), an Atari 400, and two Amiga's. Each one has a display that's much better than the previous one, and my 3-year-old iBook's tops them all. And remember, Apple is constantly improving and upgrading their monitors. They get sharper, brighter, and faster. No doubt the 23" iMac will look much better than its predecessors as well. I see no reason to avoid an upgrade just because you're unwilling to upgrade the monitor as well. Even if the monitor wasn't automatically included in the base price, a new iMac is still an fantastically powerful computer at a very fair price.
I'm no expert, but I think one of the reasons Apple is so successful now, is that they manage to convice us (the typical users) to upgrade our systems much more often than typical PC users. Most of my PC -owing friends are working off systems that are 5+ years old; my Mac friends are all newer than three years. So Apple is selling nearly twice as many machines per user as Dell or HP. Over the course of a lifetime that really adds up!