The Times surveys several new books about JFK. Perversely, the one that I'm dying to read is the one about Lee Harvey Oswald in Russia. (I will also give the Dallek a look, as he is always worth reading.)
The Jeff Greenfield book that imagines what might have happened if JFK had lived sounds like a fun thought experiment if you're the one writing it, but honestly the three paragraphs in the review completely satisfied my curiosity about Greenfield's conclusions.