Best CPU cooler on the market

I would say Thermalright is the best in my experience.
Currently the Silver Arrow and Archon are great choices,
Both come with the TR TY-140mm PWM fan which is excellent.
The SA is a double tower design with two fans similiar to Noctua's NH D-14.
http://www.xbitlabs.com/articles/coolers/display/therma...
http://benchmarkreviews.com/index.php?option=com_conten...

The Archon is an innovative design 170mm tall making it an excellent solution for those with all 4 dimms filled with tall ram kits.
http://www.xbitlabs.com/articles/coolers/display/therma...
Even the Thermalright Ultra-120 eXtreme Rev.C is an excellent choice for 1366.
http://www.thermalright.com/

The Super Mega, Noctua NH-X14, Tower 120 Extreme with beefy duals fans are still the best, but the extra $30+ you spend over a cheaper cooler like the Zalman Performa and TT Frio is barely going to give you better temps.

Though if yore on a stock cooler now and don;t want an extreme OC< any heatpiper tower cooler with dual 1200mm fans would be a huge jump/

at the high end theres very little difference in performance and some of that can be explained via the coolers tim. davcon has posted some nice coolers that are reasonably priced just be aware, not all are designed with the smaller cases in mind.
my personal choice is the all copper thermalright true,. copper being a better conductor of heat than most semi precious metals.

what i have found though is that even a cheap cooler like the thermolab baram can give just as good cooling if you pair it with the rite tim and fan, as a much more expensive option like the megahalem. we are talking less than 1 degree for half the money...
my old bram cost 20 pounds. the yate loon fan 7 pounds, zalman grease 6 pounds so 33 pounds total. the megahalem cost 45 pouds without a fan... go figure...
currently im using a cnps10 flex with a yate loon with mx4 compound again just as good as many coolers of x2 the price.