Artic Silver has undoubtedly produced high quality thermal pastes and adhesives for years. Even though Id be stupid to say that it will produce the best for years to come, at the minute, AS5 seems to be the best.
I cant vouch for it fully as when I went from AS3 -> AS5, I changed heatsink and fan which dractically changed temperatures and noise. Most people on these boards probably use Artic Silver and that is good enough for me. Ive been pointed in the right direction for every question I have asked. From motherboards to mice, thermal paste to thumb drives, the general consensus of these forums guides me in the right way.