I think currently Intel's Core2Duos are better than their AMD counterparts. Correct me if I'm wrong though.
Currently the best CPU's are the X6800 and QX6800
the AMD 6000+ is not far off, and will sometimes beat the E6600
but AMD's new CPU's are going to come out mid this year, which should be significantly better than the Core 2's
Currently, the K8 CPU's have an IPC of 3 clock cycles, where the Core 2's have an IPC of 4
the AMD K10 CPU's, according to AMD, will have an IPC of 4.
Combined with their onboard memory controller, 4GHZ hypertransport speed, shared L3 cache, and various enhancements to improve prefetching and latencies, a 2.9GHZ K10 should really give the Core 2's a run for their money.
*edit*
N0toriou5, your sig image is broken.