AMD has introduced a new dual-core Phenom derivative: the Athlon X2 7850 Black Edition.
This dual-core offering is based on the same 65nm silicon as the quad-core Phenoms. AMD has simply disabled a couple of the cores and left the 2MB L3 cache intact (plus 512KB of L2 cache per core). At 2.8GHz with an unlocked upper multiplier, this CPU has a suggested retail price of just $70—about half the price of the 2.8GHz, triple-core, and 45nm Phenom II X3 720 Black Edition.
Newegg already has the chip in stock for a dollar less than the official MSRP, and with free shipping. That puts the newcomer right up against Intel's 2.5GHz Pentium E5200, which AMD claims to have lower performance for the money. The Pentium's power envelope is a good 30W lower, though.
Update: This post originally referred to the Athlon X2 7850 as a 45nm processor. That was incorrect; this chip is in fact based on 65nm silicon.