Black Ops isn't an extremely demanding game. It ran pretty well on my 470.
I haven't tried it on Metro 2033 as I just got my card and had limited time to test it. It ran pretty well with my 2x460s OCed, so I don't see why it wouldn't run very well with a 470. I also doubt you'll see an advantage with 8GB of RAM; plus, your Cas 7 memory is better than the potential Cas 9.
Why would you spend the money on a new CPU when you're not really limited by it? The only reason to really consider a CPU upgrade would be if you were trying for 3-way SLI or something. I would just go with the 580 since that would be the performance limiter in your case, IMO.
A i7 procerssor is unnecessary, an i5 processor wil be enough and trust me it does its job well.
If you buy an i5 you can use some money on other parts, and you could easily oc your cpu(although this will not be necessary).
If your wondering if the i5 can take black ops it surley can even without being overclocked.
With a good latency 4GB ram and a decent gpu you'll be fine.
Oh and a tip for you buy a big case so you can upgrade later on
I already have the i5 760. This thing flies. Just fancies the extra 4 cores for other data intensive apps. But atm just gaming.
The GTX 580 will be the one. Don't think anything will run slow on this system for at at least a year
I don't like big cases. I had the core i5 on a mini itx board inside a sugo 6. But the biggest PSU available is an SFX 450w. So I have now moved it all into a sugo 3-F micro atx. Enough room for 2 cards and a 1500w (max) power supply). Leaves me with plenty of room for future upgrade...could get an mATX board with 2 GTX 580 in SLI with 1366 core i7.
But for now i think one GTX 580 will rock. Thanks for all your help guys.