I saw Jimmy Page in the late 80's. Its my favorite because I kind of idolize him. He played "In My Time of Dying" and it was spectacular. I've seen YES several times and they are great live.
The last concert I went to see TOOL. They are just a step above, most of the time several steps.The concern was phenomenal. easily the best concert I have ever been to sound-wise. They are very workman like. They barely move. If you are going to because you want to see crazy guys jamming all over the stage living the rock and roll dream you are going to be severely disappointed. But just the awe inspiring sound is worth the trip. I would go weekly for the experience. lol
I would have loved to have seen Rage Against the Machine. Just the pure energy would have been amazing.
Least favorite was REM. That concert actually made me dislike them. In fact I don't think I listened to them since.
Zeppelin would be my #1 concert if I could have ever seen them. ... and if I could have gone to see Kiss when I was 12 that would have been something I would have never forgotten.