I am presently reading A War Like No Other by Victor Davis Hanson about the Peloponnesian War from 431 to 404 BCE. Hanson is very conservative (see this rant of ideological cherry picking), but the book reads well and after slogging through most of The Landmark Thucydides by Robert B. Strassler, it is a welcome summary of the war. Not as complete as Peter Green's Alexander to Actium, though, but then that book is a tome.
Eventually, I will finish The Landmark Thucydides, if only to say I did. However, after reading Hanson's rant, some Marx might be a welcome change, either Karl or Groucho.