I like movies based on comic books. Unfortunately a lot of them are mediocre and some are really bad.
Based on the trailer I decided to watch Iron Man although I never had read one of the comic books. And it was really worth the visit because it is an excellent movie. It is full of action and humour and (remarkably in a superhero movie) very interesting characters. Especially Robert Downey Jr. as Tony Stark is brilliant. His portrayal creates a character which is unlike any superhero you have seen before. And he avoids the usual pathos with ease.
If you like good entertainment this is your movie.