Consumer wise it's the i7-3930k and 3960x. For the XEONs as the other person noted, it's the E5-26xx and the E5-1650 is pretty badass.

You can still go higher than these, but the prices skyrocket on the E7 line, eg the E7-8870, and the core to core value isn't higher:

http://ark.intel.com/products/53580/Intel-Xeon-Processor-E7-...