Prepare to be TOTALLY spoiled, diving just does not get any better. I am planning our 4th year in a row for this June. There are several things that come to mind right off the top of my head. First, you really need transportation on the island. We find the 4 dr crew cab truck to be ideal, seats 4 adults and plenty of room in the back for all your gear.
Unless you just really love boat diving, don't purchase the boat dive packages. There are just too many places to shore dive, esp on your first trip and if you decide that you do want to do some boat diving, you can always purchase them when you get there. The NITROX packages are not a bad idea though, for about $100 US more you can get unlimited NITROX. Well worth it in my opinion.
Money, I understand it is a little bit of a pain to exchange Can $ (have to go to a bank ect). This is second hand, but I have heard that it is a lot easier for you to get USD at home and take US$ with you. USD is accepted almost everywhere on the island except in some very small places. You will get your change in guilders (mostly). It's not exactly correct but an easy way to estimate cost in guilders is 1 guilder= $0.50 US (it's actually very close to $0.56 but 50 is a lot easier for me to keep up with). Major cedit cards are accepted most places and there are several ATM's on the island that give guilders or UDS.
Water and food are great, no worries about unsafe water or unsafe food (within reason, just as anywhere you can get bad food, happens in the US all the time). There are lots of places to eat.
Places to stay. There are a bunch of good places. My preference is Buddy Dive
www.buddydive.com . They have a "Dive and Drive" pacakge that's hard to beat. It includes airport pickup, 4 dr truck, condo, breakfast and unlimited tanks for one price. Other places that I can recommend are Sand Dollar, Lions Dive, Captain Don's and the Plaza. There are a bunch more, these are just the one's I have personal knowledge about.
Let's see, trans, money, food, hotel, diving....whats left? Crime...mostly hipe, don't leave anything of value in vehicles and don't take anything of value to remote dive sites and you will be fine. I like to take a solar shower along with us on the shore dives, nice to rinse off with fresh water after the dive. Try checking out this board as well
http://www.BonaireTalk.com/newsgroup//messages/board-topics.html There are a lot of good people on it and any question you have about Bonaire canl be answered there. You can also try doing a search on it as well. That help? Be happy to answer specific question via email if you like.
Oh yea, there is a $10 US marine park fee that you must pay and go through an orientation before you can dive and there is a $20pp exit tax you have to pay at the airport.