The Lascala 14M may be the best home theater PC case I've used.  It's elegant and simple to work with.  As a desktop format case, everything is open and easy to quickly set in motherboards / etc.  I'm currently using this with a full ATX board (a 780G) but the case is large enough with good ventilation that it allows for the use of full format PCI-E x16 cards.

The cooling provided by the case is more then adequate.  While the fans are a slight bit louder then I wanted (I have since changed them for the panaflo whisper) the unit even out of the box is quieter then most I've worked with.

Unlike many HTPC cases, this unit provides plenty of space internally for drives - so those of us who are mounting up a lot of components can find it easy to give plenty of storage space to our HTPCs.

 

One caveat: the power supply mount is VERY tight, and some power supplies will have difficulty being shoe-horned into this case.  So keep that in mind.