Let me rephrase that, for you specific-minded/"just google" people...
Do you believe the low end i7 would have more core-system gaming longevity than the core2duo? I see some DD3 ram for like 100 for 6 gigs (probably a cheap brand, I know) and i7 motherboards for a few hundred...doesn't seem like a major price difference to me for a non-uber i7 rig?
The i7's definitely much faster. The price is much higher too. I'm running the EVGA board, which is ~$300, but you can find one for ~$200 if you bargain hunt. Thats considerably more that a LGA 775 board. The procs themselves are more money, though generally you can find C2D/Q for similar prices but much less performance. the 920 is very good, and OC's beautifully, so it'll be good for a very long time. Gaming-wise, it has a decent boost over the C2s, and that gap will get larger once more games are optimized for quad-core. $1600 will get you a great i7 rig (no monitor, case or PSU- I recycled).