Sci-fi must-reads?

Well, list some and I'll read away like a constipated god.

P.S.
I read Dan Brown, so feel free to suggest intellectuel books.

>>6
Oh come on, I was just trolling.

I've read some by Asimov, Heinlein and Card -- which books in particular do you suggest I start with (I prefer shorter stories, so don't go suggesting some massive series 'kay).