Probably to the past, as the future is something I find a bit frightening. Not saying the past was less frightening, but at least we know it was there, I'd be afraid of accidentally time travelling to the end of the world or something.
As for the exact year, if I don't get to come back, probably only a few years, but if I do get to come back, probably a lot farther back so I could document some important parts of history that the knowledge of was lost for one reason or another.
That being said, if time travel technology does happen sometime soon, I'm honestly not convinced I'd feel comfortable time travelling.
I would time travel to 2004 so I would have a entire year left to spend with my dad and ask him questions that I have unanswered that I will never know the answers to now
If this time travel means so you can just watch what's on going and can get back afterwards to the point where you were before the travel, I'd definitely travel backwards to veeeeeery ancient era, and witness all the process how this planet and creatures have been changing, from the beginning to this day.
And if this time travel means having to stay where you traveled to, then I'll go backward, to where I still had someone I loved and she was still alive, being happy with me. I'll absolutely get back to and stay there forever.