Best light for a camera that runs off the camera battery!?
 

I am looking to purchase a light for interviews and such. I want a light that will run off the camera battery (I assume this is how it is done when there isn't a battery belt involved), or a light that runs off batteries (9V etc.).
Any suggestions?

For which camera, David? Canon HV20? That would be either the Canon VL-3 or VFL-1. Both of these lights attach via the Advanced Accessory Shoe and get their power directly from the camera's battery.

I have a several different cameras here, I was hoping to get a universal that wouldn't require a specific brand. I have seen the 3Watt ones, I just am not sure if that is going to be enough light...

Well if the stipulation is that the light runs off the camera battery, then it's a question of which specific cameras, since each manufacturer has their own proprietary battery form factor... there's nothing universal.

If It was me David and you are using a canon then I would seriously consider
A VL-10 Li Version 1 or 2 Which is the 10W with it own attached rechargable
Canon Battery, I know it's not running off the camera like you requested, but I consider that an advantage instead of disadvantage, It's a bit more expensive option but worth it in my opinion. , Lights will Zap your camera battery quicker the heck,Especially a 10W model . I prefer a seperate battery model Because when you are not using it you have a spare
battery for your Camera, and when you are your not gonna kill you camera
in no time.. As far as a 3W light I would not waste your time, it will only provide very marginal lighting at best 3 to 5 ft at least the 10W will give you 6 to 10 ft. The 3w or the 10W running on the camera will reduce shooting time quite sharply, I am using the VL10 Li and like it a lot.

Robin,
Thanks for that. Since you have experience in the field, that helps make the decision easier. I like the look of the one you suggested, now it is a matter of trying to get a good price.
Is the light diffusion decent? I am hoping the light won't be too harsh for the on-the-fly interviews...

David the light diffusion could be somewhat Better, But ITs not too bad. The Range is about 10 to 12 FT max with 8ft being ideal, at 10ft the spread is about 8ft wide, It can tend to look a little spotlightey In a wideangle shot.
The Light is very White Because of the Halogen lamp and this can be somewhat disconcerterting to your subjects if you are really close.. Iam sure you could rig up some kind of diffuser for it though.. Short of a complete off camera lighting solution though I think it does a good job and offers many advantages over a camera powered light.