This is not easy to pick out a cpu. There are so many cpus that have great price/performace. The 8500 is $190. and the E8400 is 170. For a cpu of that speed at that price its one heck of deal. Then there is the workhorse Q6600. AMD's 9950 black edition is $180.
Then there are the E7, E5 series. The AMD black edition x2 5400 for $77. Basically all of the X2's have great price/performance. It all comes down to how much money you want to spend. There are great price/performance cpus from both AMD and Intel in every market but the high end.