[comablack783]

Smaller PCs suffer from overheating issues, infact I work at a university and we stopped ordering SFF and USFF (ultra sff) because we were getting capacitors that would over heat and bubble which would cause system board failure. Of course this all depends on the brand, these were dells... If your looking to save space MAC mini is hard to beat.

Apple - Mac mini - The most affordable, energy-efficient Mac.

Shuttle makes some pretty small cases.. heres there competition for the mac.. atom... gross..

Newegg.com - Shuttle XS35-704 Intel Atom D510 1.66GHz Intel Socket BGA559 Intel NM10 Intel GMA 3150 Barebone

This MSI is a little bigger, kinda nice..

Newegg.com - MSI Hetis G41 Intel Core2 Quad / Core2 Duo / Celeron Intel Socket T(LGA775) Intel G41 Intel GMA X4500 Barebone

a few more..
Newegg.com - Shuttle SA76G2 AMD Phenom II / Phenom / Athlon 64 X2 / Athlon 64 AMD Socket AM2+ / AM3 AMD 760G ATI Radeon 3000 Barebone

new egg is awesome...

Newegg.com - Foxconn NT-510-A-B-A-NA Intel Atom D510 Intel NM10 1 x 200Pin Intel GMA 3150 Nettop Barebone