A friend and I are trying to come up with what we each think is the best live song from U2, based off of the bootlegs here. So far he's got With or Without You from Paris 07/04/87, and I can't refute it (yet). It's probably been asked before, and completely subjective, but interested in hearing everyone's opinion on the best song ever performed by the boys.
Check out Streets from 1989-12-26. Powerful opening snippet, amazing energy, great performance from all four members. Add the excellent audience and 5-star sound quality and that equals perfection for me.