Copied for another post:
Well currently I think people are pretty spoilt for choice when it comes to good coolers of all different styles.
I would rate the following I think all which have been mentioned: (alphabetical order)
Asetek Vapochill Micro Low Noise
Artic Cooling Freezer 64 / Freezer 4
Big Typhoon
Scythe Ninja
Thermalright XP90/90C/120
Obviously some have slightly different performance but they are all within a similiar sort of range - or perhaps even better said - all very capable of cooling an overclocked CPU.
Of course, they also do have important differences such as weight and size which could be other factors to choose on.
However, ultimately, it just comes down to choosing a cooler that fits your sort of air cooling in your case - direction, speed, noise etc and more importantly cost!
For my most recent build for a family member I used the Asetek Vapochill and have got very good results (not overhyped as some have said/reported - just ensure a proper installation*). Temps with an overclocked 3500+ to 2.6ghz at 1.5V (which is pretty hot/high thermal output) posts temps in a P180 case are 43C load (prime95, large FFT, room 22C) or 46C absolute max with room about 25C.
Those temps are with the Asetek on about 2/3ds power so prob around 8V.
*(I recommend the DFI installation method for all motherboards + ensuring thermal paste is covering the whole base + the base is absolutely centrally placed and thus completely covering the CPU)
