Unless weight or space are major issues, I think the best way to go is a Katadyn pocket, with some MP-1 tablets(chlorine dioxide) as a backup(not so much in case the filter breaks, which is extremely unlikely to ever happen, but it's good to have backup anyway since the tablets weigh almost nothing, and you may be injured or otherwise unable to operate the pump).

This filter is one of the most expensive, heavy, and relatively slow, but it is by far the most durable, simple, and easy to clean and maintain in the field. It will easily last a lifetime, or several, as long as you don't lose it. Plus no batteries or chemicals to replace or expire(though after many years you may need to replace the O-rings).