I just recently upgraded my graphics card to a 8800gts 512 and have been thinking about upgrading my CPU as well. Currently I have my E6400 oc'd to 3ghz without any problem. My main concern is if the CPU is holding me back at all, and if so how much. I have read a lot of posts but having trouble finding a direct answer on if its worth it or not.  
 
 
thnx

That cpu is still good. Wait a while for upgrade.

Nah, unless you are gonna play a very intensive CPU game like Flight Simulator X. Even then the performance boost will not be phenomenal.
 
If you do video editing or encoding, then yes, an upgrade would be good.

I agree with the last two posts.  Anything you upgrade to now will not be a substantial improvement other than a feel good upgrade, IMO.

I think with a CPU like that, any upgrade at this point will be marginal at best unless you plan on doing some extreme overclocking to reach 4GHz and beyond. Having 2 more cores at 3GHz won't immediately help you unless you use highly multi-threaded applications.
 
I agree with the top posters. Save the $ and wait for the Nehalem! =)
I hear that it promises to put the Penryn to shame in performance.

 
 
That made my 1024 x 768 swell to 1600 x 1200...