For our last few days in Bali, we went to see the rice terraces in Tegallalang, hiked up the volcano Mt Batur to watch the sunset, and drove north to the paradise diving town Amed. It was incredible place to be, and I finally got to see a sea turtle up close.
Ubud is a pure Bali paradise. As a relaxing retreat you will love all the yoga, spa, infinity pools, sustainability and beautiful nature. We went to swim in a bunch of picture perfect waterfalls and went urban exploring at the abandoned hotel "Ghost Palace".
Nusa Penida is a great place to visit when in Bali. It is nice and quiet, has some beautiful places to see such as the very famous T-rex cliff, and you can easily get around by car or scooter, before sailing back to the mainland. If you are into diving, this is a likely place to see manta rays.