For most practices the Xeon E3-1230 or higher (latest version is the best, but marginal difference between generations.) Currently, the Xeon E3-1200V3 series is widely available but the new V4 and V5 versions should be out soon.

If you want to go desktop, Intel Core i7-4790. Earlier versions up to the i7-2600 should also be fine. Again there are marginal improvements in performance, but the latest is the best. Avoid the K variants, e.g. 4790K. While they are faster, they lack some business features like Trusted Execution Technology and vPro. The K CPU's were designed for gamers and enthusiasts who like to overclock.

Here's the funny thing, the server (Xeon) processors are actually cheaper than their desktop counterparts (Core i7)

Sandeep Luthra | LTMedical.net
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