Things to consider:
1. Color temperature: Halogen bulbs have been the standard for years due to their ability to render colors well. LEDs tend to have a very narrow spectrum, and can be a bit one dimensional...... however....... with a slight bit of filtering, possibly light amber or magenta, you can begin to achieve natural skin colors. Check out the LEE filters website. They will often send, for free, a 'filter swatch book' which contains virtually all of the their colored gels, and which happen to be the perfect size for several 1" filters for an LED flashlight.
2. Variable brightness: A common mistake is to think that you need a lot of light for the on camera light, when what you actually need most of the time is a fill light. The idea is to balance the light output of the on camera light to give a natural feel to the scene, that is, so that it doesn't particularly look like there is a light on the camera. Too much light and the background will become a sea of darkness as the camera's aperture shuts down to compensate for the extra brightness from the on camera light. So, you want to balance the light on the camera to match the background lighting, both in color of the light, and level of brightness.
3. Flood: Soft, soft, soft. Keep the light diffused and you get much more pleasing results. Here again, the 'swatch book' from LEE filters has a bunch of excellent diffuser screens to help any light, but of course, if you select a floody light to start with, you will have less do with the filters/diffusers.
So..... which lights do this. Well, my NovaTac is superb for this application, as it has an excellent tint to start with, and 22 brightness levels to choose from. I've also fashioned a filter holder by cutting out the center of a water bottle cap. It slips right over the end of the light, which fits in a mic. holder attached to the top of my camera. I got some excellent diffusion material from FASTCAR which works well too.
But just about any small AA or CR123 light will work with the proper diffuser and color filtering. Remember, video and film is a gaffers game. Experiment, play, try lots of different things to see what works for you and your situation. Have fun.