You should not be experiencing over 500 Watts unless you have two heavily overclocked GPU's and a heavily overclocked CPU. http://techreport.com/articles.x/17618/15
Just out of curiosity, are you already running two 5870's in Xfire or are you planning on doing it or is your PSU giving you problems? Your Corsair 750TX is a very good power supply and you definitely should have no issues running it.
To Start Press Any Key'. Where's the ANY key?
If something's hard to do, then it's not worth doing
You know, boys, a nuclear reactor is a lot like a woman. You just have to read the manual and press the right buttons.