Till now was MX3 - from now IC Diamond - I received free TIM's from Innovation Cooling LLC for testing and it is amazing stuff, much better than MX3.It is very easy to use, just aply some in the middle of your CPU, put your Heatsink and here we are.Temps 4C less than on mX3.
I got also Ceramic (IC Perihelion)one, but never tested yet, will do soon.