Crysis will run fine on just about any modern CPU as long as you have a dual core, it really needs a beefy video card though. There are a few games that need more CPU power, such as Microsoft Flight Simulator X and GTA IV (I think?), but if you're not playing those then you don't need to aim for a high end quad or anything. If you do a fair amount of photoshop with very large PSDs and CPU-intensive filters you might want to go for a quad though. But I'd be looking at making sure you have plenty of RAM first, because PS will chew that up faster than it will CPU time.
I wouldn't bother going with an i7, stick with an i5 or Phenom II X4 955/965. Of course if you aren't interested in saving money then by all means go for something more powerful (not really worth it), but avoid the i7 980X unless you really just want to burn up cash because it simply won't benefit you in the slightest over CPUs that are a fraction of the price.
I have an i7 920, but if it wasn't for the fact that I do rendering I would not have a use for a CPU with this amount of processing power (I also got it half price
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