What are some good Wolverine, Spider-man, and Iron Man graphic novels?

I've just recently into comic books thanks to Watchmen and V for Vendetta. After reading those two I decided to go after my favorite superheroes. I've read a lot of Superman, Batman, and Green Lantern and I've realized I haven't read much Marvel. These are the three that are my favorite and interest me the most so please some give suggestions. Links to places like amazon or any page with info would be appreciated. Please only graphic novel format I would rather not track down single issues graphic novels are easier to find. Also, for Wolverine it doesn't just have to be Wolverine, I don't mind if its and X-men book.