The diving around Bali is both excellent and varied.  There are literally hundreds of small dive outfits all vying with each other for your business so decide what type of dive and be very clear on your experience levels.  The drift dives off Nusa Penida and Lombongan are full on drift dives and if you go up to the wall at Mengangen don't expect to keep to the 18m Open water rule. Presently with the absence of the Australians in large numbers, picking up dive partners can be a problem. All of the dive firms are very competitive about price and actually need persuading to take smaller groups than they are used to no matter how much money is offered (for instance Mengangen is 3 hrs from Kuta and normally a trip for 4/6 they will take you solo for $190 that's for two dives with equipment in great corals).  The dive companies do not offer this though as they think it is too expensive!