The Mrs and I went to see This Is 40 last weekend and Graham Parker was in the movie as one of the subplots. (Pretty good movie BTW - there are a couple of scenes that music fans will probably appreciate more than others.)
Anyway, I had heard of GP but other than a couple of songs, I had never paid much attention to him. He definitely has some songs worth checking out if you're a fan of someone like Elvis Costello.
Graham Parker was one of the outstanding talents to emerge out of the '70s. His first two albums, Howlin' Wind and Heat Treatment, are two of the best of the entire decade. Indeed IMHO Howlin' Wind is one of the greatest debuts ever.