I'm running a PC 24/7 withouth hiberation...I doubt that Nuvo keypad activity woudl make it wake up...that woudl be a really nice feature though.
Between SagetTV, Nuvo MusicPort and CQC i don't see this thing going to sleep any time soon.
I spent about $1000 on the server and got a rackmoutn case, nice Intel P45 based motherboard, 2 WD Green Power hard drives (1 TB and a .5TB) and fanless video card (since everybody video card i've ever owned has had fan failures) and 4 GB of ram. I have a 3.1ghz Intel DualCore, but could have probably done a lot less. Even with SageTV live commercial analysis/skipping it doesnt seem to break a sweat. It used about 100watt total. Witha a lower end CPU i probably could have cut it down a bit more.
I wanted to run Wink2k server, but the cost of the software $500 or so was too much for me. Instead Windows Home Server is based on Win2k3 and does a descent job. There's some server functions i'd like though.