What would have happened if the CIA the KGB you and me the OswaldBot 2000 missed his target on November 22, 1963, allowing John F. Kennedy to finish out his term? You can never prove a counterfactual, but I think the evidence is pretty strong that (1) the country would have suffered through the Vietnam War anyway, and (2) the president probably would not have been able to pass a domestic agenda that was anywhere near as sweeping as LBJ's. Put another way, the liberal nostalgists who dream of bygone Camelot would probably like that timeline even less than they like ours. (A question to ponder: How would it have affected the '60s protest movements to have a Kennedy instead of a Johnson in the White House?)
If all that New Frontier nostalgia is getting you down, I've got one Kennedy link for you that is mercifully devoid of reverence: Paul Krassner's classic hoax "The Parts That Were Left Out of the Kennedy Book," which many readers took to be true when it first appeared. Published in 1967, the piece pretends to be a series of outtakes from William Manchester's popular tome about the assassination, The Death of a President. It begins with some material that was well known to journalists but had not yet been reported, such as the president's infidelities, and then it grows steadily less reliable, culminating in…oh, I won't spoil the ending for you. But I will warn away anyone who doesn't want to read anything involving Lyndon Johnson's genitalia.
Bonus link: I talked about JFK conspiracy theories on Canadian TV this morning.