I didn't vote in the poll either.
I think the top was about to fall over, but if it did, that doesn't necessarily mean that the "reality" world wasn't actually a dream. I understand the significance of the top and everything that was said about it, but it could easily be just another dream layer, which Leo's character thinks is reality but isn't. The top would then of course be part of the dream, and it could be meant to help keep him from realizing he's even in a dream...it could even be a tool specifically designed by someone else to convince him that his "reality" is not a dream, when actually it is. And as Jeff mentioned, this would also mean that reality was never actually depicted in the movie.
That said, I wouldn't be surprised if Christopher Nolan doesn't even have an entirely established idea about whether or not reality is depicted in the movie, but undoubtedly, whatever scenario he thinks in his mind is simply whatever brings him the most satisfaction. I agree with what Joey said on this- the ending is there to make you smile, to make you think...but I don't think it's meant to be taken as a definite sign that the last scene is not reality, it's just meant to leave you thinking of the possibilities.
I absolutely loved Inception...which is a pretty rare thing for me to say about a movie. If movies of that creative caliber were more commonplace, I might care about movies as much as I do about music! And speaking of music, I bought the score of Inception the day after I saw it... Some of Hans Zimmer's best work yet, in my opinion. I've been listening to the last piece from the film, "Time", before falling asleep the last few nights, and it has given me massive chills every time. It never ceases to amaze me how many different things can be done with 12 notes, or how a really simple melody/chord progression can be intensely emotional.