X Pro and LED Lighting
I don't have a Fuji (waiting on the XE-1) but I have a 5D MkII and use LED lighting for fill, it works great! I purchased the Flashpoint 312 LED light from Adorama for a couple of reasons. First, it uses both daylight and tungsten temperature LEDs, so you can adjust the color temperature to your liking. Second, at $135 it's very inexpensive compared to other lights with the same features.