I find lists interesting, and may post some of my own statistics some time. I like Piston and Harris, but for me Carter is another Richard Strauss (only if it's very very early work), and none are at the top of my American composer list, which starts with Cowell and Hovhaness.

My favorite French composer is Saint-Saens, so ...

Martinu! I enjoy his music, which I once called "crisp, crunchy" in a review, but I haven't been moved to enlarge my collection. LvB, DSCH, and RVW are all favorites. I'd listen to more Simpson if I weren't so busy admiring his books on two other favorite composers, Bruckner and Nielsen.