Cooler Master's Vortex TX
As you might expect from the name, Cooler Master's Vortex is almost circularly symmetric when viewed from above; its heatsink is made entirely from copper, a (presumably) solid core with fins radiating out, a stylish transparent four-pin fan sits on top of it.
Its half kilogram weight put it in the same class as Gigabyte's offering, but its 92mm fan makes up to 36dBA of noise (26dBA minimum when used on motherboards supporting the four pin PWM connector) - it's not quiet cooler.
The Vortex is fairly compact as performance heatsink's go, sitting in a 92 x 92 x 60 mm cube.
K8 installation involves a motherboard back-plate, the last step of installation involves tightening some nuts on the back of the motherboard - not only do you need to remove your motherboard (and everything attached) to install this heatsink, but you'll need to remove it again if you have any problems (and we did have some, see the testing section) or want to change your processor. Bad planning.
Once in place the Vortex looks grand, you can't really argue with copper and transparent plastic.