What are your favorite stories about Shazam/ Captain Marvel?
Superman in Action Comics # 768 was just a great comic very funny and a little trippy if I remember it correctly. I would also say the Superman/ Shazam First Thunder was an excellent book; I would buy a series with Superman and Shazam hands down. It would be just epic two very different sides of the same coin.
The Jerry Ordway series is great. Unfortunately it started with a graphic novel, which is unavailable here.