My Top 5:
1. Ancient Rome/Meditteranean
2. Middle Earth
3. Dinosaurs
4. 1990s
5. Late Middle Ages
Life! Don't talk to me about life.
Apart from the 90's, they all seem pretty grim unless you're well off. I was a teenager in the late 80's to early 90's so if I could "visit" the 90's it would be a bit of a thrill.
share1. Some imaginary avatar-like planet
2. Under the Sea
3. In the Clouds (for vintage heaven realness)
4. An amusement park with only my guests, lets say Disney World
5. The 60s, can't you tell?
Marvel Universe. I'll have a go at being all the best characters with the coolest powers.
The 1990s
college
Other than that I'm not sure. Living in the distant past doesn't appeal to me. Hard labor, no medical care, bad food, brutal political and social rules, religious superstition, etc.
Maybe living on some virtual hippie commune where I can experiment with drugs. That would be fun.