Well you want a AM3+ motherboard because the the new AMD cpus.When they come out if you want to upgrade you just need to replace the cpu. Also I'd look at getting a better power supply. I don't know if that HEC one is good but I know for the same price you can get a good psu. For that price range I'd do what Outlander stated and just copy the TH $500 build. It's a great build for that price but upgrade to the AM3+ motherboard you picked out on your second build.