Steins;Gate, a Japanese light novel and anime, includes John Titor in the story in an awesome way. It also includes some bit of hacker culture that I think is more real than the typical American movie "hacker". I recommend it! Edit: As pointed out in the comments, this was originally a visual novel! There are many ways to enjoy this story.
Strong agree. Stiens;Gate is the only time traveller story that I know that establishes rules for time travel early on and actually sticks to these rules till the end.
IMHO, Steins;Gate hasn't clarified what time travel really represents. When one travels from one world line to another, does the previous world line still exist? Is time travel a travel between parallel universes, a complete rewrite of history in the _same_ world, or something else?
In the first Steins;Gate anime, it seems that time travel means a rewrite of history (i.e. the conventional type of time travel in science fictions), but in Steins;Gate 0, time travel seems more like jumping between parallel universes.