I have a Quantum Calcu-Light XP. It has a measurement range of -7EV to 21EV for ISO100 film. Both reflected and incident and very accurate against my Minolta III F and various camera bodies that I trust. It has a digital readout with memory recall, is amazingly sensitive, and the batteries last for years. The meter is discontinued but you can pick them up on eBay where I got mine.
This is a minor legend of a meter and will work in darkness. However, with digital I find that my best shots at night are found by putting my D200 at f16 and then bracketing by exposure. I usually have 1 minute, 2 minute, 4 minute for example. These times are for scenes with artificial light sources in them for the most part.The files don't look great until you can get them into Photoshop and then the magic happens. DSLRs are superb for night work. One caveat, the long exposures eat batteries. I have my camera welded on 100ASA and also have the long exposure noise reduction on. This takes a second exposure after the first. So, I have a 2 battery set up on the D200. (Soon to be D800 btw

. I also shoot in RAW at the highest possible quality. Here's a (copyrighted) sample or two of my nightwork (these are 72dpi - the prints are awesome!)
I found this website very good for technical info and some great night shots of Cambridge, UK.
http://www.cambridgeincolour.com/