Returned from Bonaire yesterday. Both my wife and I are divers, and it has to be one of the best dive destinations there is. All of the above posts are right on, including the one about beaches. I would highly reccomend Bonaire for someone who wants to dive a lot, but not for a non-diver. Little shopping, no great beaches, etc. I was with a group and stayed at Buddy Dive.
I would add that staying at a resort would be a better idea than renting a house or condo. They have a considerable crime issue on Bonaire and the resort provides a level of security. To give you an idea, if you lock your rental car, you void the insurance because that almost guarentees a break-in. You have to leave nothing in the vehicle and leave the windows down and the doors unlocked!
We had no problem, but a guy I know that rented a condo three weeks ago and had packed all his gear for an early morning departure. They broke into the condo and stole everything he had. Laptop, dive gear, wallet, passport. The door had been jimmied so many times, it couldn't be properly locked. I felt very secure in the Buddy Dive resort my entire trip.