Ever since the release of the Intel Core i7 Quad core CPUs, the prices for everything else has been on the decline. Some of these CPUs are some noteworthy models are below $250.
Intel Core 2 Quad Q9300
6MB L2 Cache
1333 MHz FSB
For a low price of $240, Amazon.com has Newegg beaten ($274.99). For a few build, I would recommend this CPU because it gives you more bang for your buck right now.