I don't run a front light all the time but do on gloomy days (weather, not me) or when I'm heading into really tough traffic areas. I don't always have my Planet Bike Blaze 2W headlight mounted or in my underseat bag, but I always have my "EDC" or every day carry flashlight with me, even on 2 hour training rides. My EDC light is a small but incredibly powerful LED flashlight, a single AA powered Fenix LD10. That plus the TwoFish Bikeblock another has mentioned up thread make a great system.

On strobe I'm plenty visible - it is by far more visible in this mode than a Planet Blaze 2W on strobe (which is also a good choice too). It might even be too visible/annoying.

Some that go this non-bike specific flashlight route like the 2 x AA format better - you get slightly more output and roughly double the runtime - but for my purposes I find the shorter single AA format works best. Less overhang on the bars and it is roughly the same length as my PB light. Weighs only 50 grams (without batteries). My extra "runtime" is simply extra cells stored in the underseat bag rather than in the flashlight.

One nice thing about the flashlight/twofish combo (another reseller has a 3 pack cheaper) is that you'll have another tool in your arsenal for purposes other than biking alone. These small powerful lights amazingly useful.

PS: If you do go this route you'll want to invest in a decent charger and good cells. It'll pay for itself quickly.