I've seen Pink Floyd twice (in the 80's) and they were excellent.
I just recently saw 'Wish You Were Here' which is an EXCELLENT 'tribute' band to Pink Floyd. They play a lot of the early stuff (Syd Barrett days) and they usually play the entire Dark Side album start to finish. The really cool thing is that, while they stay true to the feeling of each song, they do what Floyd did and 'improvise' a bit. Just enough to keep it interesting, yet not enough to ruin it. They also have a pretty decent light show and they utilize the same type of screen that Floyd used in the Division Bell tour.