I've sold quite a number of books that use time travel as part of the plot.
Sean Ferrell's MAN IN THE EMPTY SUIT
Patrick Lee's GHOST COUNTRY
And a number of books that imagine a very interesting future:
You won't be surprised to learn that one of the questions we toss around when all these gents gather at the bar is "if you could travel in time, both forward and back where would you go, if you could go (and return!) to just one day."
My answer is pretty easy (remember of course that I'm a practicing Catholic): I'd go back to the time of Jesus and hang out with him and the fellas just as closely and for as long as I could.
When would you go?