Best Thermal Compound

It doesn't really matter. There won't be more than 3C difference between the best and worst compounds, and most fall within two degrees of each other. AS5 is fine if you still have some. If you don't, I think MX-4 is slightly better.

ArticSilver 5 is still in the top three in every review that has been recently published and the two that beat it were only one degree better. I advise you stick with Artic Siler 5.
Here is one of the latest: http://www.hardwaresecrets.com/article/Thermal-Compound...
Here is another article from 2008: http://benchmarkreviews.com/index.php?option=com_conten...
Tom's has not done an article in a very long time.
Just make sure you are using a fairly fresh tube of what-ever therman compound you chose.

Artic Silver 5 is still used and is considered the best , at least I think it is and I have tried some others but have always come back to Artic Silver.

Artic Cooling MX-2 or MX-4 is just as good and no need to cure and isn't conductive.

I Use artic Silver 5 and it does work!. Just make sure you get a fresh tube of it. I wish it came in a bigger tube but oh well