Casual Gamer: Q6700 bottleneck?

I'm a power user, but only game casually. I like to game at high resolutions, I play Civilizations IV Colinizations, Age of the Empires III, Madden 2008, TrackManiaNations, and a little Call of Duty 4/Battlefield 2.

My current rig:
Q6700 (stock cooling, undervolted .125volt)
Foxconn Geforce 256MB 7900 GS-OC (factory overclocked almost 50%)
2x2GB Gskill PC2-8500 1066MHZ CL5.5.5.15
Gigabyte GA-P35-DS3L 2.0
Windows XP SP3/Windows 7 Dual boot
24" 1920x1200 LCD Monitor

I use Office 2003/2007, Adobe Design CS4, and a bunch of networking tools (VPN/SSH/RDP)

My games run decent. I know simply putting in a better graphics card will help somewhat in the games, but I want to increase overall system performance. I'm wondering if how much I would have to spend to get a decent upgrade, or if I should invest in a better CPU cooler and try overclocking. Energy costs & noise are an issue, so I haven't done much with overclocking.

I saw this one on the Egg...Would it be much of an upgrade?

E8500: http://www.newegg.com/Product/Prod [...] 6819115036
Q9200S:

I know the graphics is bottlenecking. I'm asking about the CPU. Is that bottlenecking me much? I'm not just concerned about graphics performance, but overall system performance. I'm not one of those diehards that keeps my system processes to a minimum. It's a home/work PC so I run ~70 processes. Am I going to see much of a boost with a E8500 (going from 4 cores to 2 cores) or a Q8xxx or 9xxx?

It's G0, I'm 99% sure.

Q6700 is only GO Stepping http://processorfinder.intel.com/L [...] =&OrdCode=
I agree, Better HSF and current Video Card

What is that going to do for my energy costs & noise? I.E if I have to overvolt it and use bigger HSF, would it be cheaper over the course of 2 years to by a faster, more energy efficient model?

mi1ez I want your Q6600... mine cries at 3.3
Anyway, energy cost won't go up all that much compared to what your system already sucks down, noise won't go up at all because the S1283 is quieter than the stock intel HSF (larger fans are generally quieter).

Buying a new, more energy efficient CPU won't pay for itself in the home environment if you're replacing an existing CPU, they're mainly targetted at either new systems, or places where you've got dozens of systems running.

Agreed, do NOT upgrade your CPU. You would see only marginal gains and it would cost you $250+ to get them. Overclocking or the move to 8GB/64-bit are your two best options.

http://www.frostytech.com is probably the best place for heatsink reviews. Not sure if it'd fit in your case because I'm too lazy to look up the specs... it fits in my Antec 1200 though... not that it's much help knowing that because the 1200 is huge... ^^;

Just noticed the video card... at those resolutions you really want something with upwards of 1GB RAM... Personally recommend the ATI HD4890, if it's better than the 4870 then that's one hell of a card (get a 4870 if the 90 is outside your budget range)