I watched this movie so many time in film studies. I had to do a "shot by shot". The first few times I thought it was fantastic. The next few brilliant. I think Inception was a better film from an entertainment standpoint - but Momento will probably remain his best film - for those of us that have it memorized ;)
note to self - watch Momento again.
We too had to watch Memento in film studies, in the film editing class :)
If you really think about how it was structured, pure cinema.
He makes messing around with time look easy.. the movie is incredibly complex if you want it to be - or simple if you dont. One of the few where the surface story is interesting - and the deeper story is even more interesting. One of the best in the history of film IMO.