I agree, BA, as both a Christian and not I've never believed in hell. Hell, insofar as it exists, belongs in this world.
I don't know about Matt but on my loose neopagan path the underworld is a concept. It isn't a place of torment but it is the counterpoint to 'above'. We have dark deities - they aren't evil but will take us to the depths before we can emerge, re-formed. For me this is a useful concept to use when considering the difficulties I've encountered on my own journey, to make peace with them and see the gifts within.