This would basically be the computer I would consider buying; although, I've been considering waiting until Penryn. Because the memory controller hasn't been upgraded to 800 mHz, the fastest memory you can use doesn't really take advantage of Santa Rosa as I understand it. I don't know if this would be solved by the time Penryn is available.
My current G4 iMac is still chugging along. In fact, it works fine. The only reason I'm in the market is the small screen size, old GPU, and occasional extended beach ball.