There are (at least) two wonderful versions of Drowned Lovers/Clyde Water by Nic Jones - the Penguin Eggs track with concertina etc is great, but much darker is the solo version on Game Set Match which as far as I can tell uses open C tuning (CGCGCC). Trouble is I can't play anything else using this tuning, so I try to play using drop D (with capo on 2) - you can get some of the impact of the latter version without the hassle and audience (ie friends) irritation factor of extensive retuning.