Bali is a lot of different things for a lot of different people. If you're looking for a luxury spa or a beachfront property, there are many inexpensive resorts in Nasi Dua or Seminyak that cater to all tastes and budgets. The island's coasts feature beaches suitable for doing nothing or a whole lot of diving and surfing. If you want nightclubs and chaos, choose Kuta or Sanur.
But if you're looking to feast your mind and your soul, Ubud is where you should head.