Antec Aria case - FREE to a good home (although if you're outside Wellington, I'd appreciate it if you pay the shipping costs). Review / pics: http://www.silentpcreview.com/article146-page1.html 

This was an HTPC for a long time and served very well. It can house a micro-ATX board with four slots for expansion cards. Includes a PSU; note that it's the older 20-pin ATX standard.

I also have a Asrock P4i65GV board (Pentium 4) and CPU (P4-type Celeron, from memory)  that used to live in it. Also free.  http://www.asrock.com/mb/overview.asp?Model=P4i65GV