My favorites lately have been from a company called Klarus. They're some of the best lights I've ever had. And the interface is absolutely the best in my opinion. I buy most of my lights from www.goinggear.com if you want check out more flashlights than you've ever seen in one place!
Amp draw is less than 5. And they are wired to factory harness and switches so the key has to be on. I have no need for them to be on without it running.
I'm kind of a flashlight junkie so I usually have at least two on me and all of them are super bright!