My friend Laura posted 50 shows attended, and I responded with a very quick list of 50. My friend Annie posted 50 shows with comments and mentioned that "50 is not a very big number." She's right, 50 is not that many bands/musicians, and my earlier list was kinda dumb.
As it happens I had a kind of list on my computer of my favorite live music performances ever, though it was sort of tentative and incomplete, but it even had some web citations and stuff where I found precise dates. So I dug it up and updated it a bit. Here they are, not in any particular order.
Ween (930 club, 10/28/96)
We were near the front of the stage, I nearly died of euphoria when I heard "The Blarney Stone" for the first time in my life. This was after their country album and before The Mollusk, some of their awesomest material. They were backed by a bunch of Nashville session players. Amazing.
Journey & Foreigner (Nissan Pavilion, 7/13/99)