Ubud is a must for a couple of nights. I love the place. Take your pick from loads of great hotels there.The temple dances are spellbinding at night. Its a very interesting place and there always seems to be a festival on so its just as good during the day. If you like a lot of nightlife then Kuta might be for you- it wasn't for me but it might have been 20 years ago!
Get a driver/guide for a couple of days. There is so much to see in Bali- it really is a paradise island.