Since I lack pictures, I figured I'd report my results here rather than doing a general gallery posting.
Mobo/CPU: GIGABYTE|GA-C1007UN-D R
SSD: 64GB CRUCIAL CT064M4SSD2 R
RAM: 2Gx2|GSKILL F3-12800CL9D-4GBRL
Drive: LG CT40N
PSU: PicoPSU-150-XT plus 12V power brick from an old Shuttle Barebones
Case: Morex 3777, without its power components and fans
Fan: Noiseblocker NB-eLoop B12-PS
Windows 8 Professional 64-bit
Purpose: as noted above, mainly music plus streaming audio. It can play discs, but if I was building a PC for disc playing I'd use a full-size disc drive with motorized tray (and case to match), not one of these feeble laptop drives.
Power consumption: 23 watts playing music; 26 watts streaming video. Drops to 2 watts sleeping.
Cooling: According to an IR thermometer the hottest thing is the NB heatsink, typically 15-20 C higher than the CPU sink. I also found that with only the tiny CPU fan, the system reported temperatures around 60-70C, which I realize it can probably handle but which worry me. After experiments I removed the CPU fan and mounted a 120mm higher fan just under the top of the case, with a cutout. Kinda like this mod https://picasaweb.google.com/1068691874 ... 5856134226
but with the fan closer to the back right corner. The Noiseblocker has good sonic characteristics and is easy to tweak via Speedfan. An Antec tricool on its lowest setting would probably be almost as good, though.
So at least for this application, the thermal constraint is probably not the CPU, but the NB.
Windows 8 notes: I ran into UEFI problems on installation; in the end setting BIOS to pure UEFI in all things worked. Since then, apart from the stupidities of the Win 8 interface which I hear will be fixed, it has worked nicely. Wake-on-LAN works without a hitch, as does Remote Desktop Connection.
Thanks for the help here and on other threads.