Your system is pretty well balanced, though your CPU may not be able to keep up in some instances. This is more the games' fault in not being optimized, rather than the CPU not being powerful. Can you overclock? Also, I'm basing the above on you having a Q6600(quad-core), not an e6600(dual-core), though neither WoW nor BF2 would run that differently on the quad vs the duo. Can you find out for sure which one you have?
You don't need to replace the thermal interface material (TIM) ever if you put it on right the first time. If you have a good HSF, then you should be able to start overclocking. Make sure you're monitoring your temps during stress tests and that you know for sure what the thermal junction max is for the Q6600. From what I've seen, you should be able to hit 3.0 GHz without too much problem.
Ah yes, WoW is quad-core optimized now. It wasn't last time I checked, quite some time ago. And I was just guessing about BF2, since it was such an old game, but EA is good about those things. So I stand VERY corrected. But the principle is still there, an overclock will help you out a great deal.