A beam that would be acceptable on any DOT approved headlight on a motor vehicle. One that lights the road and not the eyeballs of an oncoming driver. One where the beam lights up the road evenly, getting brighter as it goes out (required for even illumination) and cuts off at the horizon so oncoming drivers are not blinded.

In other words, the kind of beam that is required by law by most vehicles on the road, and by bicycles in countries where bicycles are taken seriously. As opposed to conical beams, which are "OK I guess" if you're trail riding and need to see branches that might smack you in the head, but on the road, they just mean "we just got some crap optics left over from flashlight manufacturing because they were cheap, we're not REQUIRED by law to do any better than this and you don't have a better choice, so give us money."

Check out the beam shots on this page. Notice that the light cuts off abruptly just above the surface of the roadway.

headlight beams from Peter White Cycles