So the limiting factor, size wise, is what video card you want for your gaming. For example, a GTX 460 or HD 5850.
With a card that size the case that will fit a card that size will also fit a micro-ATX motherboard.
Nice find on the case.
At 13.58" x 8.94" x 10.71" (W:227mm x H:272mm x D:345mm ) in size that's a BIG mini-ITX case, as big as some micro-ATX or HTPC cases. It also fits full size PSUs and video card.
GTX 460 is a good choice - it's a bit shorter than HD 5850, and uses a modest amount of power and isn't that loud either.
GIGABYTE GA-H55N-USB3 and I7-860 or i5-750, with a GTX 460 and a 450W-550W modular PSU should work out well.