For me I just hate building mATX systems cause they are too small lol
, other than that I use the board that best suits the job if it is mATX, EATX, etc. Last system I built was an ATX board as I built a gaming machine using the QX6850 system. So in the end it is the results that matter to me, as long as what I want to put in the machine fits with the slots so there is no comprimise.
I think with the Gigabyte board it should do the trick, only addon would be a firewire card if i get a second Shaw box. Other than that once the machine is built i will post back how well it work, so far I am impressed with the price everything for around 1600$ most expensive part is the HD/BD player from LG.