Tom's Hardware published a CPU buying guide
A quote from the article:
Whether you’re building or upgrading a new PC, the CPU matters a lot. Increased clock speeds and core counts can make a huge difference in overall performance, providing a more responsive system, smoother game play and faster turnaround on intensive tasks such as video transcoding. Plus, the chip you choose will also dictate your motherboard purchase, as each CPU requires only works with a specific socket and set of chipsets.How to Buy the Right CPU