Spec me a HTPC

[Ripper]

On a bit of a merry go round deciding on a new PC, but i'm looking to build a HTPC for the living room. As well as using it for various media I would also like to be able to do some casual gaming. I'm looking for:

• Something as quiet and small as possible (case no wider than 25cm - no higher than 30cm if possible)
• It must be black to fit in with my other equipment
• Include an SSD (128gb preferably) as well as a 500GB drive alongside
• 8GB RAM
• Windows not needed, will use W8 preview until full release. Keyboard/mouse also not needed.
• £500 max

I don't really understand the difference between mATX and mITX so I will leave it in your capable hands to spec me the right system! Cheers.