The Grand Hyatt is an excellent resort Hotel, but Nusa Dua is known as the "Golden Ghetto".You could be anywhere in the world.No locals allowed in unless working.The "Shopping village" just outside the gates of the Hotel is designed just for the tourist.Generally prices are at least 20/30% higher than anywhere else and the food a very poor immitation of otherwise excellent bali food.
If you want to experience Bali, stay in your hotel as little as possible, take a taxi to Kuta if you want to buy cheap things or a taxi ride to Ubud (about $15 for all day if you haggle with the waiting taxis in the hotel car park.) Its full of local craft shops and the like.The Monkey Temple is fun but make sure eberything is attached as the little bu***rs will pinch anything they can get their hands on, even specs.
Always walk down to the taxi park and haggle prices rather than get one at reception.You will alway get it cheaper as they will all try and get your business.
Get out of the "Ghetto" see the island, meet the people, eat the food, you certainly wont if you stay in the hotel all the time.