Nissin Di866 Flash
External Flash and Strobes.
Wesley is using the Nissin Di866 as an alternative to the Nikon SB-900 Speedlight - read his review.
It's interesting to note that the color temperature of the illumination from the Nissin flash is warmer than what you'd get from the Nikon SB-900.
Here are two sample photos that Wesley posted in that forum thread, which are not visible unless you are a registered user:
