The Ice Light by Westcott is a $450 light source that many photographers swear by. It is a powerful, variable LED light that can be hand held and gives a nice directional strip-like spread.
Then again, it costs $450, which is no peanuts. If you are in the photography stage where you have more time than money, photographer Justin Barr made a DIY version that looks pretty nifty. Details, after the jump.