I think it's well worth it, and I wouldn't bother re-building with an old rim. You can even buy pre-built wheels that are a good value. I have one I bought a couple years back in the USA with a Sanyo hub and a no-name double-walled rim in a touring width, shipped, for $100 from an e-bay seller who is probably still active.

I wouldn't go back to other light sources for bikes ridden often in the dark.