If anyone is considering going small I have just built a pretty decent rig in ITX form factor as an HTPC.
Coolermaster Elite 120 Advanced (swapped the front fan out with a BeQuiet Shadow Wings SW1 120mm PWM jobbie)
Asrock Z77E-ITX
3770K @ 4.2
Zalman CNPS 8900 Quiet
2x4GB GSkill TridentX 2400 CL10
128GB Vertex4
2x3TB WD Green
Corsair AX850
Win7 Home Premium with XBMC 11 Eden
Runnin off the onboard HD4000 GFX which is more than sufficient for 3D
Connected to my Yamaha 671 AVR and then to the Samsung PS51D490 3D plasma. Speakers are Dali Concept 8 fronts and a Concept centre. No Sub or rears for now.
Still busy building as I’m waitng for the CPU cooler and AX850 to arrive but I had it running with stock cooler and a 600 watt CM silent pro giold PSU and was pretty impressed. Unless Docking is running it’s pretty quiet.
I also have a Lenovo N5902 multimedia keyboard that makes controlling everything pretty easy.