I have a Light & Motion Urban 300 light that I’ve been using on the MVT for the last year or so, in addition to a separate rear blinker. It comes with a helmet mount, but I found it a bit awkward so I just strap it around the handlebar. It’s plenty bright for the trail and has a flashing mode for when I’m in the city.
The rubber strap allows for easy removal (provided you remember!) but is still grippy enough that it doesn’t shift when I hit a bump. As an added bonus, it allows for easy adjustment of the angle of the light. When I see someone approaching I’ll point it down, and then tilt it back up after they go by, so I’m not blinding anyone.