If I had a time machine I'd check out the fall of the Berlin Wall and see The Smiths and Nirvana in concert but beyond that and a couple of other things I'd probably never visit the 80s or 90s again. The former were dreadful and I've already lived through the latter once so I'm not all that interested to see them again. Give me a time period I've never seen before, like say the 1800s but do something weird like put me in Italy and give me a mundane but ultimately peaceful occupation like a librarian or shoe repair man.
I'd probably go to 2472 to find we gave up colonising space and instead migrated to underwater cities where we live in daily fear of squid attacks.