That's s tough one. There are definitely two sides to Hot Tuna. There's the 'pure' acoustic side, best shown by their first album simply titled "Hot Tuna Live from Orleans House" which has Jorma, Jack, and Will Scarlett (on harmonica). This was what drove me to want to play guitar. The latest release of it features a number of bonus tracks not on the original. Their third album, "Burgers" is a good mix of acoustic and electric, and features "The Water Song" and (the one that turned me on to them electrically) "Sea Child". In between there's "First Pull Up Then Pull Down" which contains acoustic songs performed live in a raw, electric format. While the sound quality leaves something to be desired the energy is intense.
I'd have to say my favorite is "Phosphorescent Rat". It has more Jorma-penned songs and is a good mix of "mellow" and "hard" rockin' songs. The later records tend towards a harder rock sound.
Actually, looking at the songs on "The Best of..." it looks as if this 2-cd set would be a great introduction. -