Zalman HD135 HTPC Case
 

The Zalman HD135 Media PC case was designed to be low-profile, yet you can install full-height video card(s) in it without the need for a riser card. It is also possible to use a standard sized power supply and a regular optical drive. Space for storage is also plenty, you can stuff up to 6 HDDs in this case which is just 135mm high. The HD135 is made from all aluminum and is available in black and silver for a price of $299.