
Theoretically I just won a light meter on eBay. It's an incident flash meter and will come in quite handy.
There are, broadly speaking, two kinds of light meters, incident and reflected. The one built in to your camera is a reflected meter, it reads the light being reflected from your subject. An incident meter is the one you see the photo assistant waving in front of the subject that has a little pingpong ball sort of thing on it, it measures the light falling on the subject. It's usually more accurate than a reflected meter since a reflected meter will obviously be affected by the colors being worn by the subject.
An incident flash meter takes an incident meter one step further and lets you accurately meter studio flash setups. You plug the sync cord into the meter, move to the point where you want to meter, and hit the test button. It fires the flash and then meters the light emitted by said flash. It also works as a non-flash incident meter.
I had a wonderful incident meter, a Sekonic L-398, for quite a number of years. Unfortunately it's not a flash meter, and when we started doing studio lighting, it turned out to be producing erratic readings. So basically I haven't been using it much.
Well, now I will be getting a spiffy little Minolta flash meter in the near future, I'm just waiting for the seller to contact me. It'll probably be my last photography equipment purchase for a while. It's pretty inexpensive, only $108 with shipping, I just can't afford a lot of gear right now. Fortunately I don't need any additional gear right now, though I'd love to find a sweet deal on a used large format view camera....