Don't build an ITX system unless you go to LAN parties often. I have a Prodigy build and I wish I went with an ATX build because it's very limited to upgrades. Plus the prodigy is the size of most mATX cases but weighs more then most of them because it's all steel.
Edit: Also I would suggest that you pickout a mechnical keyboard.
So...AMD? Thanks for your help! The reason I didn't choose a mechanical is because of the price but I will get one soon (Christmas or when I've saved up enough {IBM Model M from eBay?}).