Help with system purchase for sage / hd playback

[dj7675]

Looking for some help. I want to build a system for sage. Requirements are below:

-reliable playback of hd
-Very quiet
-fit/look nice in an av rack
-usb in front/back
-firewire

I had been considering the dell xps200 as a nice pre built system and changing the video card, but after some reading of reviews some claimed it was very loud. Then I considered the Dell GX620 as several had said that it was extremely quite but didn't have firewire on front and looked a bit "pcish" in my av rack. I would prefer to go with a pre built and ust change the video card, or a nice barebones system that had the case, motherboard, and powersupply already to go.

Budget somewhere between 5-800.

Any comments greatly appreciated.

Darin