We have just posted our review of the gargantuan NH-D14 CPU Cooler from Noctua.  This cooler is the largest unit we've seen and it comes with a couple of large fans for your cooling pleasure.  The design is a bit different from other large dual-fan heatpipe coolers, but it seems to work out well for them.  While the price tag may scare off some people, you should consider it if you want high-end performance without introducing liquid cooling into your system.

Noctua NH-D14 CPU Cooler (aka. Noctua Behemoth) - BCCHardware