http://www.piriform.com/

Running CCleaner has never hurt in my experince

Uninstalling bloatware and keeping background programs to a minimum helps too :)

First off, your mobo and cpu aren't compatible. The cpu is 1156 and your mobo is 1366. If you go with 1156 you won't need triple channel ram either

What res do you game at?

No, it can't be used as an upgrade.

These Maybe?

I've read good things about the Cogage true spirt which is pretty cheap.

If you put a single 4gb with 2 2gb it won't run in dual channel though.

What speakers or heatset do you use? Its really not worth it to get a soundcard if you're just running some crappy speakers imo.

I would guess the major improvement in the 6800 series will be in tessellation which is really where the current gen of ATI cards are being killed by Nvidia

rainmeter = win