Windenburg is great for sight seeing and playing as a tourist, but then it is one of the most well made worlds they have, as the previous post shows.
Mt Komorebi is also good, with its bamboo forest and many shrines to visit.
Brindleton Bay has the lighthouse and the pet cemetary - which is conveniently close to a museum.
Del Sol Valley has the road with the famous plaques, the view in the pinnacles, possibly going to see the houses where famous people live if that is your thing.
Sulani mostly has beaches, but also the waterfall and (if clean) the turtle hatching.
Tartosa has the tree and the funny face in the water, possibly the square (though horrible opening hours).
Selvadorada the temple
And don't forget that you can make your own sights. I built a cathedral and roman bath in Windenburg when my sims were honeymooning there, and I've built a botanical garden in San Myshuno and a little town square in Glimmerbrook - so build your own sites as well.