Hi. I've had good experiences with 2 dive ops in Bali:
Aquamarine - I believe the owner is British (instructors and DMs are from all over the world). Very friendly, professional and efficient. They offer pick up for most of the island (for a fee) or you can go to their shop.
http://www.aquamarinediving.com/
Tauch Terminal at Tulamben (they have their own hotel so you can swim in the pool or dine at their restaurant in between dives) where the famous Liberty wreck is. I believe the senior instructor is from Australia, but they employ many Indonesians as instructors, DMs, staff and even the ladies who carry your gear to the entry point for shore dive. There are several good dive sites ("The Drop-off/Wall", "Coral Garden" etc) from the Tulamben beach aside from the wreck. For boat dives, they arrange everything, including lunch, and drive you to the boat. Very low prices, they offer discounts if you bring your own gear. Friendly staff (most do speak some English). You have to get there on your own, but they will take you back to hotel (for a fee).
http://www.tauch-terminal.com/english/index1.htm
If you're looking for dive site recommendations, I'd definitely check out the Tulamben wreck (go early before it gets crowded) and it's great for night dive as well; Secret Bay for muck diving; Nusa Penida (drift dive and it can get chilly from updraft) for awesome coral gardens and chance encounters with the Mola Mola and other larger animals. To some extent, your choice of dive sites might be limited by where your hotel is as it takes >2 hours to get from one end of the island to the other (there are no highways on Bali), but thankfully there are plentiful dive sites all around Bali, so you can still get a good dive even though you might not get to dive a particular site.
PM me if you need more info.
Have a great trip and Dive safely.
