Anyway, as long as you get what you feel your money is worth, no one can tell you otherwise. Be happy and games on.
As for your 8600GT, they might be able to run SLI natively, I am not too sure about that. Running natively means that you don't need a bridge over the two cards and the SLI is running software-wise. You need to check on the web for more information.
Good luck with your computer built be sure to tell us more about it when you are done....
