I built my PC with a $400+ motherboard too... but not because I thought that it would be good for gaming. I usually catch HDD failures early and am able to recover data before the situation gets out of hand, but on my last two builds it was the motherboard that finally made the computer non-functional. This time around I invested the extra cash in the hopes that the mobo would be of higher quality and last longer than 5 years.
I'm not that much into gaming anymore, but I do build my PCs with high quality components. I'm not trying to start any shit, but why is a $400+ motherboard good for gaming? There are cheaper boards that can run lots of ram and multiple graphics cards and overclock. When I was into gaming I always thought that SLI and crossfire was a huge gimmick. Just get one good card and you're good to go.