Garcian's build is pretty nice, but the RAM is a little overkill. Might as well get a better video card while you're at it and you can look into playing games on higher settings.
Newegg/TigerDirect ftw.
In all though, building is the better option. Pre-built PCs are stupidly overpriced. It's not that difficult, you can probably find a guide to building your own computer online along with warnings on what not to do. Do a little research, and save a lot of money, and get a better product in the end.