water cooling.
j/k lol.
what do you need it for, what kind of cooling is it?
CPU? System fan? Case fan??
Nowadays, all-in-one, closed loop water cooling, like the corsair h100i are very popular for CPUs.
Non-water, the CoolerMaster EVO 212+ is considered the best price/performance cooler, with the Noctua DH14 being the best cooler for temps alone.
For case fans, you have a multitude of choices, depending on your case, their placement, your silence/performance requirements, and even the colour.