Ok here are my results that I pulled when I recorded them when I still had the Q6600 before upgrading (Direct X 9.0c, Resident Evil, Fixed benchmark, Catalyst 9.9)
Q6600 @ 3.4ghz, 6 gigs of ram, 4890
1280x1024 4AA = 60.8
1680x1050 0AA = 57.8
1680x1050 4AA = 57.8
1920x1080 0AA = 54.6
1920x1080 4AA = 55.1
Core i7 860 Stock with Turbo Enabled, 4 Gigs of Ram, 4890 (no overclocking), Cats 9.9:
1280x1024 4AA = 110.3
1680x1050 0AA = 98.7
1680x1050 4AA = 90.9
1920x1080 0AA = 89.4
1920x1080 4AA = 82.1 (+49%)
1920x1080 8AA = 77.6
Core i7 860 @ 3.9ghz no Turbo, 4 Gigs of Ram, 4890, Cats 9.9:
1280x1024 4AA = 111.5
1680x1050 0AA = 106.0
1680x1050 4AA = 89.3
1920x1080 0AA = 94.7
1920x1080 4AA = 81.6 (+48%)
1920x1080 8AA = 77.3
You can ask someone else with a similar setup (Munky above) to verify these numbers or run your own and see what you get with your setup. Of course this is only 1 game. But you can add GTAIV to this list and Dragon Age as well. WinRAR extraction, Distributed Computing, conversion of FLAC into MP3, you name it. IF you don't do any of these, obviously you won't see benefits of Core i7.