If you are searching for story of the movie, this may not be the right place for you. I am not going to take away the suspense of what actually happens in the movie. The film was released with a lot of speculation about how the ten kamal characters will be related and on what the 140 Million has been spent on ? The movie was neat and clean. Kamal Hassan has done the ten roles with perfection and shows that "Ulaganayagan" is in fact a title well suited to him.
After watching the first half i thought the movie belonged to the hollywood action film genre, since the first half was filled with ruthless killings and breathtaking car chases and some geeky stuffs and jargon which would be difficult to pickup for a normal guy. After that the film moves on with beautiful screenplay taking care of the weak story and you don't feel bored during the whole 3 hours.
Each and every important character that you see in movie is only Kamal. It was difficult the ten characters played by him at the end of the movie. Kamal in villain role needs to be applauded and it happens to be my favourite. Some characters were not necessary but probably added to exceed the count of nine characters already done by veteran sivaji.
Asin comes along with the hero for almost the full length of the movie but fails to impress but irritates with her repetitive dialogues. Mallika, as usual included for a skin show, but looks like most of the scenes were eaten by the censor board :) Other characters, not much to mention.
There are too many ways to interpret what kamal has tried to tell in the climax. Anyway watch the movie and decide it by yourself. Incase you have problems, refer to this http://en.wikipedia.org/wiki/Chaos_theory. We had a discussion among us for 90 minutes after reading the page and what kamal has tried to say in the movie. But do read it only after the movie, not before that.
To end, Dasavatharam is a great work by Kamal and is a movie worth spending money and time. Looks like a trend setter for tamil cinema, that is recovering slowly from the love for masala movies.