Use this as an HTPC/Steambox. I have XBMC/Plex server installed as well as Steam running Windows 7 OS.
The confined spaces and 450w PSU limit were constraining but neither kept this build from being great. I did have to return an HIS gfx card that was too big and drew too much power.
I have done a few revisions like finally adding the better CPU heatsink and the accelero xtreme which dramatically reduced my temps and noise.
This rig runs most of my games at high or ultra settings and gets me 60fps or higher. Far Cry 3 was the most demanding game and I was scared to play it before replacing the heatsinks as the fans would hit 100% speed and the temps would skyrocket into the 75-85 degree range.
I have seen some watercooled setups etc. but I didn't have any luck with that and using a full sized gfx card. If you are looking for a good form factor and the ability to run a full sized gfx card this rig will not disappoint.