I've also been looking into this. Iv'e decided on the Whelen Talon. It's not the cheapest dash light, but it is the best I've seen. Very bright and a lot of options. (21 patterns on the duel light) We have one as a rear light in an SUV and it's clearly visible from a distance.
I'll be buying one shortly in the hopes that it will increase my visabliity. I have an old strobe light bar that just doesn't demand much attention.
"The answer to this last question will determine
whether you are drunk or not. Was Mickey Mouse a cat
or a dog?"