Are any of my components going to bottleneck my 6870?

Your power supply should be enough and 4GB of RAM is pretty standard these days so I do not see a problem there. The 2.66GHz Quad Core should be fine to start off with and is easily overclockable (is that even a word?) to 3.0GHz on stock cooling or even further with an aftermarket cooler. A 6870 will definitely be a good card for you to get and you can always transfer it to your new system, if and when you get one as well as potentially using CrossFire in the future.

I should know, I have one myself.
-Klosteral

What's the name of that PSU?
What's your native resolution?
That quad will be happier running at above 3GHZ

It's a Rocketfish 550 W (Had to buy cheaper because I was broke at the time   ).
My native resolution is 1920x1200, and yes, I plan on over-clocking it, I just need some more cooling.

if the psu is this one http://www.hardwaresecrets.com/article/Rocketfish-550-W... it should be ok. get your cpu to 3ghz first.

youre fine, dont sweat it

Alright, thanks for the quick responses, guys.