I use the Corsair H series water coolers on all 7 of my systems. Easy to install, quiet, and small footprint in the case. You can actually install ram without scraping the skin off your fingers on some heatsink cooling fins.
http://www.newegg.com/Product/Produc...82E16835181017
http://www.newegg.com/Product/Produc...82E16835181019
Also keeps the cpu cooler if you like to overclock.