Regarding the Rave scene:
I have seen the movie twice now. The first time was with my parents, and I thought the rave scene would never end. The second time was with my wife, and interestingly enough, I really enjoyed it. It seems I could follow the movie to that sensual level while watching with my wife, but not with my parents. Go figure. Who you see the movie with matters!
Although I really enjoyed the movie (both times!) I do agree that it felt a bit like filler for the third movie. We do get fed a lot of new information to chew on, but plot-wise not a whole lot actually happened. The fight scenes, while super cool, felt like they were stretched out for no other reason than to take up more time. Without the fight scenes, we probably could have gotten the information we needed for the third movie in about 20 minutes.
I'm with those who think that Zion is another level of the Matrix, and I think that it is a cool concept. Some of you wiser, more knowledgable folks may consider the concept tired and boring, but it's new to me -- and fascinating. I'm looking forward to seeing what the "truth" is about the matrix.
For those who didn't sit through the Longest Credits Ever to see the teaser, you didn't really miss much. The teaser was just that, and you don't learn anything about the third movie, other than there is a showdown between Neo and Agent Smith (shocker!).
-tRR