This is quite an interesting read regarding the performance of the Phenom II processors and what sorts of gains you can get overclocking them. A system using one of these chips would be more affordable for most people.
Phenom II processors are apparently an interesting choice for overclockers, that is, they offer high overclocking potential, and they respond to raising clock rates by increasing their performance in real applications. What’s important, their performance looks attractive for a gaming PC (they will make a good couple with a powerful graphics card). You won’t have to pay much extra for the infrastructure (motherboard, coolers, PSU) for successful overclocking. However, you will need some skills to overclock processors with locked multiplier (the procedure is described above along with specific motherboard requirements). Despite high operating clock rates and even higher overclocked values, the new processors do not grow very hot. That may be the effect of integrated circuits for dynamic power management (for each core) and good characteristics of AMD’s 45nm SOI process technology.