I'll just copy my little essay...
The Core i7 gets an unfair bad rap. It had issues with a single GTX 280 that gave it a very poor showing in some early reviews. In most single card configurations, it should show (very slightly) higher framerates, with it's lead expanding more significantly with each additional card. It's hyperthreading allows it to prioritize andhandle SLI/Crossfire overhead more effectively, resulting in higher framerates, even when there is still a GPU bottleneck.
Secondly, it OCs like a son of a bitch. It is usually benchmarked at stock in reviews, and while it doesn't go to exhorbitantly higher OCs than Core and Phenom 2s, it is clocked lower at stock.
On the other hand, the Phenom II 940 is a killer deal right now. It's a full $90 cheaper than the i7 920, and $55 cheaper than the Phenom II 955 lots of people like to recommend. On top of that, it uses an AM2+ chipset, which uses DDR2-1066 and has little negative impact in the real world. (Sure, you can have triple-channel DDR3-2000, you'll hardly ever saturate dual-channel DDR2-1066, and it has lower latencies.) A hundred bucks is the difference between a 4850 and a 4890, and that will have a much bigger impact on your gaming than an i7 920 and over a Ph2 940. On he other hand, CPUs age more gracefully than video cards. It all comes down to what you value more, CPU or graphics horsepower.