This computer has seen some changes since I originally posted it back in Oct. 2007 (wow!), so I thought I'd post them. The pictures below link to larger versions.
After passing along my old desktop to my mom, I ended up with an extra Thermalright XP-120 heatsink and a 120mm Panaflow L1A fan (swapped them out for the stock AMD heatsink and fan, sorry mom). Since the combo fit under the chassis brace, I decided to put them in this computer.
Since I'd already (mistakenly) cut a hole in the cover almost directly above the heatsink, I built a small duct around the fan.
Originally, the system had two hard drives: one for OS, music, and downloaded videos, and a second drive that was dedicated to recording live TV. Both were 120 GB 2.5" drives and more than plenty since I usually delete recordings after I've watched them. However, I had a spare 500 GB WD Green drive available and another computer which needed an OS drive. So, the WD drive became my new recording drive.
Mounting it was an issue since I had neither the time or the desire to come up with something elaborate. I ended up mounting both drives horizontally in the drive tray, with the laptop drive on the bottom (soft mounted with zip ties and spare drive grommets from my Antec Solo case. The WD drive is mounted above that as illustrated in this picture:
The elastic cord is clamped to the drive tray, stabilized by zip ties where they go up before they go under the drive. The same clamps are used on the underside of the drive. It's worked okay so far, but I started out with a quiet drive to begin with. Another option would have been to do something similar in the 5.25" tray under the DVD drive, but I ruled that out for some reason I can't quite remember right now.
I've also replaced the two analog tuner cards with two HD tuner cards (AVerMedia A180) to support the new TV and put it in a new cabinet.
The back of the cabinet behind the case was cut out just slightly smaller than the case itself so there's a small overlap to seal the front from the back. This also gives me full access to all of the connections at the back of the case. The two fans on the bottom of the case and the new CPU fan bring air in from the front of the cabinet, which is then exhausted out the back of the case (along with the PSU exhaust air) and behind the cabinet.
Quick edit to add quick power consumption and temperature numbers:
Idle: 75 W
Watching live TV: 80-92 W (roughly same for 720p and 1080i ATSC sources), using between 70-90% of one CPU core.
The room ambient temp is close to 27C right now. The CPU is running at 32/34C (cores 1/2) and the drives are both at 37C while watching a live 1080i ATSC source.