The protagonist of Mark Haddon's The Curious Incident of the Dog in the Night-Time is commonly identified as an Aspie, but it's not a very flattering portrayal, and the author has been backpedaling when it comes to whether or not the character was supposed to have AS or not. I posted a topic about this back in December.
A lot of people will tell you that Sherlock Holmes is definitely an Aspie, but I think he's a mild case at best, at least in the original Arthur Conan Doyle stories. The more recent film and TV versions have played up his Aspie tendencies much more, specifically the ones starring Jeremy Brett, Robert Downey, and Benedict Cumberbatch. That last one is the only one to actually use the A word.
Tom Ripley, from The Talented Mr. Ripley and its four sequels, also has some Aspie tendencies. He was more or less the alter ego of his creator, Patricia Highsmith, and I've heard several people speculate that she may have had AS. But, like the literary version of Holmes, I don't think he's severe enough that he would get a diagnosis.