Just last year, I found Red Planet in paperback in a used bookstore; I held it in my hands, just looking at the cover and smiling, and felt such a sense of wonderment, that it was that story, over 30 years ago, that captured my imagination so much, that I would love the genre forever. And yes... I bought it, and read it that same day.
Some authors inspire me more than others... Heinlein, Asimov, and Larry Niven being my favourites.