I'd travel not to the past, but to the future. Specifically about 50 years into the future. There'd be all sorts of technological improvements, and it'd be really interesting to see how society had progressed in that time. As despite all the predictions and prognostication and whatnot, no-one really knows what the future holds, and to have an opportunity to see it would be really fascinating to me!
If I had to go back to the past... probably dinosaur time. Any period, to be honest, I'm not fussed. Just to see 'em is good enough for me! :D