The Zaman 8900 series is a good cooler. I used to use the older 8700 series. This comparison chart shows cooling ability and noise level. The 8700 ranks low on the list, but it is a compact model going up against some large and noisy heat sinks. I went with the Tuniq Tower 120 because it was one of the highest rated for cooling while it still has low noise readings. I also like that the fan is concealed in the fins so you can't get your fingers bitten.
Zalman 8700 scored 19.5˚c @ 125w with 48.1 dBA noise level. I like the models with the blue LED in the fan so you have an extra indicator that the fan hasn't failed... and it looks freaky

These fans usually have PWM speed control so you can dial it down to the right cooling & ambient noise at each level of illumination/heat.
A lot of the better designs have the cooling contact on an awkward side or position so tat rules them out. One benefit of a larger finned unit is that you have some leeway if/when the fan fails. Of course a double fan system gives you that fail safe, but they are noisy, bulky and expensive. You need to leave room for wiring, venting, suspension/mounting system, lens & reflector mounting and finger & dust guards. These requirements eliminate a lot of the CPU coolers on the list.
You will notice as you get to the less efficient models at the bottom of the list, they resemble the standard fin & fan heat sinks that we are used to seeing in the DIY LED builds.
http://www.frostytech.com/articleview.cfm?articleid=2525&page=4