Core 2 Duo 3.06ghz looks ok but i dont know if that will be enough.
Did you mean the C2D E7600 3.06Ghz or C2D E8500 3.16Ghz?
E7600 doesnt have Virtualization Technology Support like the E8500 or Q9550.
E8500 or Q9550 - either one would be a good choice.
Newegg has an quad core opteron am2 75w for only $74.99 plus shipping. You can use a gigabyte board with it. Gigabyte boards bios will recognize opterons.