The Bronze Age is over all the best era in comics history, I think, and the main reason is because of the level of experimentation that went on. The first generation to grow up with comics was writing a drawing their own stuff, with an eye toward shaking up the status quo and expanding the subject matter. Mainstream comics dealt with real-life, mainstream issues.
My own favorite of the characters to make their debut in the Bronze Age was "The Ochinaut" (Link NSFW!). This comic about a man who is shrunk down and injected into his own testicles was creative, fun, strange, and wildly imaginative. It's shocking to me, even now, that this comic was ever published, let alone had a successful 35-plus issue run.
Just how successful? The character was recognizable enough to be chosen for inclusion in a silly cross-company ad campaign involving sugary snack foods (if only for a single month), as evidenced by this page which I scanned from an old issue of Whitman's Solar Man of Something, from 1976: