Having recently released their new Core 2 Duo chips, Intel are about to release a quad core version (!). It packages 2 core 2 cpus in the same package, and uses the same LGA 775 socket, so its a drop in replacement (just need a compatable BIOS). Release date is this month !
Specs are awesome.
See
Intel's Core 2 Quadro Kentsfield: Four Cores on a Rampage | Tom's Hardware UK and Ireland
for a review.
Better get saving up me pennies !