Geoff Sobering , Aug 25, 2007; 11:00 p.m.
I usually shoot raw in difficult or unpredictable lighting situations and white-balance later.
Night shots are very tough because you may have a mix of lighting sources (tungsten, fluorescent, Mercury-arc, etc.), so you may have to find a white-balance that gives the best look overall. You could also choose a number of white-balances for different sections of the image and re-assemble them a la HDR.