To me Inception was amazingly overrated. It lacked common sense, and lacked a true sense of wonder. Don't get me wrong, I still kinda liked it, but I was floored by it's lack of creativity, because the trailer was very promising. Acting was first rate and the film was mounted well. A couple of the effects were cool (the folded urban landscape).
The story of a dream whith a dream is NOT new. But if people have forgotten, dreams distort reality, they go askew and create unknowns that would probably not make people venture into dreams simply because it would be too risky and with too many variables. Dreams are surreal, the film's dreams were vanilla.
Here's a few dream movies that people should check out:
The Lathe of Heaven: This is the PBS 300,000 dollar version not the Scifi piece of garbage. Almost only 3 people in the entire film, well acted and brilliant. Amateur effects. Approved by the author Ursulla K. LeGuin. The Lathe of Heaven book is perfect. An intelligent amazing film.
Akira Kurosawa's Dreams: It's Kurosawa, enough said.
Dreamscape: A small budget effects film in the 80's. Effects look 1/2 outdated with today's computer effects but a fun, popcorn cruncher well done flick. Closest to Inception.
Requiem for a Dream: It's a guided tour through hell for 4 people. Not much of a point but brilliantly acted by Ellen Burstyn.
The Cell: The Cell earns a place among such movie mind-trips as 2001: A Space Odyssey, Altered States, What Dreams May Come, and Un Chien Andalou. But the story lacks cohesion.
When Dreams May Come: Sad effects film starring Robin Williams. Moving of the painting-like effects were inspired by Hudson River and German Romanesque schools of painting, so I'm a sucker for that.
Just my two cents, of course, I could be wrong.