If all time travelers existed in the same timeline, it might look something like this infographic, which outlines which time traveler arrived in which year, how they got there, and what time travel paradoxes could arise.
David McCandless created this visualization as part of his upcoming book of chart porn, The Visual Miscellaneum. Here, he charts the temporal paths of different TV and movie time travelers (Doctor Who was omitted for the sake of sanity, though he hasn't ruled out making a separate chart for the Time Lord), and, just for fun, imagines what might happen if time travelers who landed in the same year happened to meet up (I suspect that, despite his ingenuity, Marty McFly would not fare well against the Terminator). McCandless did feel that his research revealed one key deficiency in time travel stories: nearly all time travel journeys he mapped originate and land between the years 1900-2100.
[Information is Beautiful via Reddit]