Kudos on the Antec 300 case, I chose the same one for my hackintosh build. The 3-speed fans on the case do a swell job of moving air silently. Gigabyte bards are almost designed to be 'toshed, and there are many that are compatable. I am currently using a P55-USB3 board for my build, it only has USB ports so a pci-firewire and esata cards were mandatory to allow full operational capacity with external drives used for video editing.
Also why use Chimera as opposed to the Tonymac/Chemeleon method? I have found that there are more DSDT modules available through this method, which helps with overal system stability.
Sweet article, now if everyone else could stop paying Steve Jobs top $ for cheepie foxconn boards. xAlso, just about any optical disk drive can be compatable so long as it is run in ACHI.
Happy Hacking! :D