Core I5 or Core I7?

Hello all, I've come to ask for your advice...

I've been out of the computer know-how market for a bit while I've been concentrating on other things, like family and school. However, I got a nice little holiday bonus and have been thinking about (finally) upgrading my Win7 64-bit rig.

I have a decent video card (geForce 460GTX), but what's really holding my system back is everything else, like the Core 2 CPU, PCI-E v1 mobo, and DDR2 RAM. The GPU barely flinches, but my CPU (especially) is slammed at 100% when I play games like DE:HR. So I'm looking at upgrading my 3 core components - CPU, mobo, & memory. Especially since the Mrs. primarily uses the PS3 as a Netflix and BluRay player these days.

I'm pretty comfortable in regards to the specs on the latter two, but when it comes to Intel CPUs, I'm a little confused. I know Core I5s don't support HyperThreading and don't have an integrated memory controller like the Core I7s do, but how important are these things? Are they worth paying an extra $100 for?

Can you help a gargoyle make an informed, yet frugal decision on a possible upgrade to his aging gaming fig? If so, thanks in advance

Only going to talk about the Socket 1155 CPUs here. I'm ignoring the much more expensive Socket 2011 CPUs.

Actually, i5 does have an integrated memory controller, dual channel just like the i7. Even the ones before the current Sandy Bridge line.

The difference, besides the price between the i7-2600K and the i5-2500K is hyperthreading and 8MB of Level 3 cache instead of only 6MB and an extra 100MHz to the base clock speed. All that for only 50% more money.

Unless you run one of the thread happy applications that review sites like to benchmark with to show the difference between the two, such as video compression or ray trace rendering, then you really don't lose much choosing the i5-2500 over the i7-2600.

Agree with Mr Xmas. The i5 2500k is good bang for the buck, with unlocked multiplier for easy overclocking, and worth the price imho. newegg reviews if you want some feedback.
http://www.newegg.com/Product/Produc...82E16819115072

Exactly the person I was hoping would see this with exactly the sort of info I needed. Once again, I am in your debt sir. This will make selling the idea to the Mrs. much easier, if I can save $100 or so off the CPU alone.

Edit: and thanks for the confirmation and extra link TS

... and I should now be getting my new hardware before XMas Thanks again you two