I have been always a big fan of The Matrix(1999) ( not what came next to that :p ). When I saw the teaser trailer for the first time I was shocked :O
I've just seen the Inception's trailer and I'm in shock state again 10yrs after :O
The trailer has some spoilers so if you liked The Matrix, Dark City, The Cell, Paprika or you simply trust Nolan... then just go directly to the cinema :D
If you can't resist the temptation and you don't mind to ruin a bit the surprise with some minor spoliers then just see the 3rd trailer !
I recommend you to download the Trailer 3 in HD quality from Apple, it really worths the effort:
Here is the official page:
This is THE movie of 2010 ! July 16th is the date.