From Ars Technica:

Intel finally brings its Nehalem architecture to its mainstream desktop PC line with today's Core i5/i7 and P55 chipset launch. In contrast to most previous launches, the chipset is actually a big deal this time around, marking as it does Intel's most radical overhaul of basic PC system architecture since the introduction of AGP.

...

It's "in theory," because Tech Report's Core i5/i7 benches show some surprising results that indicate that all isn't right with the new platform under Windows 7, and that (contrary to the stated conclusion) gamers are better off with the older Core 2 Duo systems.
Now i when i saw the more technical reports on this i was really surprised that they have made this big of a jump. If its still something that needs the kinks worked out ... I may just jump to a newer Core2 instead of i5/i7.