The Total is $496, you can give or take on some items.. The RAM is fine for gaming, although you might want 1600/4GB. The case is simple but sturdy, The CPU gives you a third processor for any games that use dual or triple core CPUs. The AM3 socket should be pretty upgradeable over the next couple years. I would prefer an AMD/ATI build, but this one would last you a good amount of time.. plenty of breathing room for upgrades.
I like the build. Personally I would go for 4GB as it is the current "sweet spot" and shows performance gains. However, the CPU and graphics card are more important. Mushkin and OCZ are good quality brands. OCZ is usually a little cheaper though but Mushkin tends to have good timings.
I would also go with a radeon 4850 as opposed to the 9800gt. It outperforms it but it is more expensive.
This motherboard supports crossfire (ATI's SLI) and costs less than the SLI one. Asus and Gigabyte are the better quality motherboard brands and also have some nice overclocking options.
My modifications (without the ram upgrade) total the cost at $10 more though.