I'd personally like to go forward into the future to see past my time.
If I had to go back in time it would be around the 17th century where I could be innovative and bring new ideas, while still lacking the necessary technology to radically change the passed. I doubt my presence in the past would create too many ripples into the future, but it's possible the butterfly effect may take hold.
Frankly it's probably not the best idea to go fucking around in our past. That is unless you take multiple universes into account, which is entirely possible when dealing with time travel. You wouldn't be changing this current time line, but one that had already been effected by your meddling.