The latest heatsink from Thermal Transtech (aka nPower) features the largest heatpipe I’ve ever seen for CPU cooling.
Kingwin’s XT-1264 heatpipe heatsink tests in the topmost rank – good for aggressive cooling.
The Aragon 900 Watercooling Kit from AMA Tech does an excellent cooling job and has all the parts you need for aggressive CPU cooling. UPDATED to show the waterblock’s innards.
The CoolerMaster Hyper N520 Heatsink Review.
Test of silver content in popular silver greases – Silversinksam