I have been there only once, just came back yesterday in fact... We had a nice combination, 3 nights in the center of Bali with visits of temples, rice fields, etc...
Then 4 days in a resort.
We stayed at the Bali Reef Resort,
http://www.balireef-resort.com/
What I liked is the size (small resort with individual bungalows) and atmosphere. You don't feel like in a tourist factory. And the staff was very friendly. Food was good, with a large selection.
The beach is not beautiful but I have been told that Bali is not the best place for beaches.
Again, this was my first time there, so quite difficult for me to compare with something else...