We (me, wife, 16-year-old son, and 13-year-old daughter) were in Bali for 2 weeks in February this year and had a great time. We spent time in Sanur, Canggu, and Ubud. It has some of the kindest, sweetest, most sincere people you will meet.
Sanur was OK, and it has some nice resorts. We found it to be a good place to get over the jetlag and get settled in. It's also on the coast and pretty close to the port. I'd recommend a day trip to Nusa Penida for one of those three days.
Ubud is inland, so more of a jungle vibe than a beach vibe. We were safe and fine at the monkey sanctuary, but the monkeys are known to take loose items that are not properly put away. While in Ubud, you can visit one of the "Bali swings" and a luwak coffee place.
We also went on a hike of Mount Batur, an active volcano (smoke, no lava). For our family, who spends summers hiking in Colorado, it was enjoyable and nice to start at such a low elevation.
Drivers are incredibly cheap in Bali ($50/day + tips cheap), so don't hesitate to find one to drive you around to various waterfalls and other sights. We booked private tours and directed the drivers to go wherever we wanted.
