"of all time" is the hardest....just the 70's alone would result in 10 (for me :P) - thinking LiveKillers, ALIVE!, Frampton Comes Alive, Strangers, SongRemainstheSame, Live at Budokan, Live Bootleg, YESSONGS, etc.
mmm.....gotta pick one from all decades....
AC/DC "If you want blood youve got it"