I went with the shuttle as well, YOu can put together a good shuttle for about $500 and lower.

I went with about $600 for a shuttle box and motherboard, 512 megs ram, and a 2.4 ghz pent.

I actually added some more cost by buying a new 80gb HD with 8meg cache that really makes it fly, its really quiet too.

Future mods coming this week is maybe the glowing front face, a TDK 52x burner , a Wireless (D-link) PCI card and a matrox triple head parhelia card.

The onboard 5.1 audio and video is excellent for games and other stuff

YOu still get one agp slot and one pci slot for anything else
with oodles of usb and firewire ports as well as network connection

www.shuttleonline.com

(follow the reviews link fr tom hardware review.
Im never ever getting a tower again