Vietnamese liberation would have been much swifter and less bloody, and Laos and Cambodia too would have avoided being bombed into oblivion. Does the US still support Pol Pot in this world?
As for the effects in the US, no big anti war movement would emerge right then, but I feel this effect would just be postponed until Americas next military adventure. All the technology and journalism is all there and ready to show the world the images of what modern warfare looks like by this point in history, it just wouldn't be in Vietnam. In fact, without being knees deep in the quagmire that was Vietnam, I can see the US being much more willing to actively intervene with troops in Angola or Nicaragua. El Che Guevara famously said that "two, three, many Vietnams" would serve to undermine US hegemony. The US also knew this, and knew they could not afford to get involved in another Vietnam like situaiton during the cold war. Without the example of Vietnam, Angola or Nicaragua would have likely become this worlds "Vietnam", and the anti war and hippie movements would have started then, as images reached american audiences.