Ditto, the head tube mount. Or fork on my comfort hybrid with suspension fork.

My AGU KlickFix handlebar bag sits up too high for bar mounting lights or cameras. But the bag isn't deep enough to block the head tube. So that's where I mount my L&M Urban 500 or Serfas SL-255 -- sometimes both, reserving the Serfas as a backup for longer night rides.

I tried mounting to-see lights on the bag but it bounces around too much, no matter how well I secured the bag. It's only suitable for mounting to-be-seen safety lights/blinkers or reflectors.

I don't trust mounting lights directly to rigid forks without something to ensure the light won't twist and snag the spokes. My Univega fork has rack mounting lugs so I could use those. But it would make better sense for me to get a front rack for the bag and mount the light on the handlebar. My road bike has no lugs. No way I'm taking a chance on mounting anything that might twist and snag the spokes.

On the hybrid with suspension fork I just mount the lights to the upper tube, which is about the same diameter as the head tubes on my other bikes. It's well clear of the wheel, no risks.