Is this a constant on light or are you planning to turn on as needed and adjust brightness? What kind of primaries are you planning to use? Alkalines are pointless so it's lithium in AA/AAA form factor (L91/L92) or CR123A cells IMO.
Illuminating a road sign so you can read it while moving isn't the most hefty requirement but it's more demanding than lighting up a cuesheet. Personally I think the
Fenix HL50 is pretty great. You can use NiMH, Alkaline, or Lithium and it also includes a small tube to allow you to run AA or CR123A so if you get stuck buying batteries on the road you're covered for commonly available AA but can use the better CR123A when you start out and have them as your spares. Low is good for cuesheets and depending on the conditions med or hi works great for road signs. I've probably 100 hours or so on mine, mostly running high with NiMH AA but often with CR123A - it's a good light.
For longer rides or more demanding conditions I use a Zebralight H600w MkIV but that's a 18650 light most likely not of interest.