Shin-Etsu is good stuff - however, it's difficult to apply. Out of all the pastes I've tried, I have probably converted to Arctic Cooling MX-2 from AS5. I have 23 tubes of Shin-Etsu if anyone wants to buy a few off of me. Just send me a PM, I'd sell them super cheap. I found them off of an Ebay seller here in the US.
Also, I heard Shin-Etsu is the best, but harder to apply. For people who don't want to go through that, there's MX-2 and OCZ Freeze.