MX-2. No scientific evidence to support that, I just prefer it over AS5. But like Oregon said, there are some charts out there that show MX-2 performing better than AS5. Spanky showed me a few awhile back...I'll see if I can dig them up.
well, i vote arctic silver 5 but its all ive ever used. the next one that i want to use is coollaboratory liquid pro... for the cpu that i dont plan on upgrading.