Julian Cope presents Head Heritage

If you're up for a bit of folk metal, then how about Finntroll? Try their "unplugged" album Visor om Slutet if you fancy dipping your toe, or the earlier Jaktens Tid if you want the full Polka Metal (I swear I'm not making this up) experience.

Also on the fun tip, try Vintersorg - either Till Fjälls or Ödemarkens Son. Or the side-project Otyg, which is much more folksy than metal - wonderful drinking songs.

NB none of the above are remotely progressive! In case you couldn't work that out.