I've replaced all my fans with some spare 120mm fans I had laying around that pull ~0.3A and move a good bit more air than the stock ones.  I have some better ones on order as well.

Has anyone had luck adding heatsinks to the front side of the chips as well for cooling?  I don't know if it will make a big difference or not, but as two of my Cubes will not run reliably in the high clock setting, I figured it would be worth playing with.