The E6600 (at $316) is faster than ANYTHING AMD currently offers in all areas. And not just somewhat faster - significantly. The Core2 Extreme, simply anihilates anything AMD currently offers.
The performance crown goes to the fastest processor - clearly, that is not AMD anymore.
Even bang for the buck, there simply is no comparison, unless AMD starts selling FX-62s for $200 a piece or the fastest X2s for $100 each.
I'm not an Intel fanboy, but Core is one damn impressive architecture, especially when you consider how much power it (doesn't) use.
edit: meant the E6600, not 6400.