I went with a Corsair A70 cooler.
A = Air; H = Hydro/Water.

It was $40, Canadian.
Not all that much.

My 2600K is stable, with a very moderate overclock to 4.5 Ghz.
The CPU runs at 40-42c, at the desktop and aren't often beyond 60c while 5-boxing Warcraft (Medium settings on the main, except maximum view distance; Low settings on the slaves, except moderate 1/4 view distance; Shadows, Weather Effects, Water Effects off & Spell Effects high enough to notice things to move out of).

Using Prime95 for a stress test, the CPU can get up to 80 celcius.
The ambient temperature upstairs at my place is 25c, give or take a couple of degrees.

I used this guide for the overclock: http://www.youtube.com/watch?v=WMZoWOpry40
It was directed at an i5 2500K, but the i7 guides I found were similar and I already had the settings saves on the motherboard for the i5 overclock.

My system is:
i7 2600K, @4.5Ghz
Asus PvZ68-V Pro
8GB, Corsair DDR3 1600mhz ram.
GTX 570, 1GB.
OCZ Vertex 3 (120GB), as the OS Drive.
64-bit Win 7, Home Premium.