Depends. If the list were relatively static I probably would keep it inline in the source like you've shown. If it were more dynamic or dependent on something outside the script I'd leave it external with a quick change from YAML::Load to YAML::LoadFile (granted I'd probably use a YAML sequence rather than a hash, but the idea is the same). It also could move to the bottom of the file after an __END__ marker and remain with the script but be more segregated from the flow of code.