For those among you who've considered the acquisition of a sometimes expensive unofficial recording, I can recommend the following shows, all of which feature good set lists & excellent sound quality:
The Kinks - Rainbow Theatre (London), 1977 (a classic)
The Kinks - Rockpalast Grugahalle (Essen, Germany), 1982
The Who - The Summit (Houston, TX), 1975 (exceptional soundboard SQ)
The Who - Warehouse (New Orleans), 1971 (more for the set list than the SQ)
AC/DC - Agora Ballroom (Cleveland, OH), 1977 (not an AC/DC fan, but this one smokes!
West, Bruce & Laing - Carnegie Hall (NYC), 1972
Oasis - Earls Court (London), 1995
Oasis - Hammerstein Ballroom (NYC), 1997 (maybe their best set list ever?)
The Rolling Stones - Tarrant County Convention Center Arena (Fort Worth, TX), 1972
Rockpile - The Palladium (NYC), 1979 (a smoking set)
Led Zeppelin - Fillmore West (San Francisco), 1969
Led Zeppelin - Nassau Veterans Memorial Coliseum (NY), 1975
The Mahavishnu Orchestra - Music Hall (Cleveland), 1972
Lucinda Williams - Boston Orpheum (Boston), 1999 (IMO a boot of unsurpassed SQ)