The ZOO TV stage was absolutely amazing in its era, but now I think it has been superated many times. In 1993 no one had used live footage of the concert while they were playing, and U2 began to do it. That's one point for Zoo' stage. Another one is the use of a B-Stage, which is an important thing to contact Band-Audience. Of course, you're right, Zoo' stage was new and great.
I like the Vertigo // Elevation stages. Thats only because of the B-stages. The best stage would be the B-stage from either Elevation or the first leg of Vertigo, but, with the POPMart screen behind the band. (or the Vertigo screens, or the ZOO TV Screens)
PopMart for most garish and awe-inspiring (where-else would you find a cocktail stick, a McDonald's arch and a giant TV screen!?); ZooTV for originality and ingenuisness (first use of of a B-stage at a rock concert); Vertigo for the blend between showpiece and intimacy