After the job you pool for me i will not come if you need me?
Indigo extreme was the best thermal condactivity 20 W/mK, Is a bit hard to apply as need’s to get the processor at 90 c it comes with 2-3 in the package as the instructions is a bit messy but worth is worth it -5 c they see anyone who tried or more.
http://indigo-xtreme.com/
The come off is a bit tricky and you may scrach the cpu surface.
There are metallic thermal pastes any metal alloy always has the best results but they always a risk as they are electrical conductive and you apply it with a brash that comes with they have and video how to apply:
http://www.sidewindercomputers.com/colipro1.html
is worth to try but the removal is difficult you may lose the warrantee as it goes deep the heat spreader microstructure.
The rest are more or less the same with PK-1 Thermal Compound a bit better:
http://www.prolimatech.com/en/products/detail.asp?id=163&page=1
Always easy to apply, remove.
Artic silver is very popular and easies to find but with ceramic 2 a bit better.
http://www.arcticsilver.com/
I say go with artic silver 5 to the stock any better isn’t worth it as it spreads the heat all over the motherboard as you know. This processor is for OC a better cooler is need NH-D14 is the best choice the assymetrical desing allows you to put heat sink memory dims and the 140x140 that gets below is cooling and the ram!! The good news about this cooler the thermal paste is very good and you don't to risk enything else exept indigo, is worth any penny!
Ps 4Ryan6 above is very experienced with these also good to read his round-up's