I'm surprised no one mentioned sunscreen...
No real need. Your wetsuit/rash guard is plenty of sun protection when you are diving, a hat and tshirt when not. No need to smear goo all over you that washes off in the water and is not good for the reef to boot.
What to take and maybe just as important what not to.
I don't bother with a SMB, you are never diving more than a hundred yards or so from shore, even when boat diving so in the highly unlikely event you don't come up near the boat, you can easily swim to shore, plus the waves are rarely more than a foot so long range visibility is not hampered by waves. Waving a fin is about as effective. Knives are not needed and gloves are prohibited on Bonaire so they can be left at home.
You will want hard soled booties, ones with tennis shoe like soles, the soft rubbery slipper type are not a good idea. The shore is mainly iron stone and coral rubble which is very hard on the feet. A small flash light or 2 for night diving is great but there is no need for anything more than simple 4 C-cell type, the 7 AA cell Ikelite work great.
For cloths, I recommend you take all the cloths you think will need and make 2 identical piles, same number of shirts, pants and whatever in each, then put one pile back up, most people take way too many cloths. You do not need much in the way of cloths on Boniare. I take a shirt per day, 2 pairs of shorts, 2 or 3 bathing suits and little else. The clean dinner shirt from the night before becomes the dive shirt for the next day. The nighs are warm so there is no need for long sleves, dresses for the ladies or any kind of "nice cloths", shorts and tshirts are fine. There are plenty of tshirt shops on the island if you need a couple more.
When traveling, be sure to keep anything valuable or difficult to replace in your carry on. I recommend carring on prescription meds, regs, computer, camera, mask (esp if it is prescription) and at least 1 change of cloths. I include 1 of my bathing suits in the mix. You can buy pretty much anything you need on island but some things are harder to come by, don't let an airline ruin your trip by losing the one or 2 things you can't easily replace.
Do not carry travelers checks or large bills. They are both a hassel and can be a problem to use. Boniare recently switched over to the US Dollar so there is no need for currency conversion. Credit cards are accepted most places and there are ATM machines all over the island so you can get cash easily.
I would suggest you take some time and read over the many post on Bonaire here. Over the years, a lot of us who know Bonaire well have posted a lot of great hints and tips to make your trip more fun, well worth the time to read them. If you can't find the answer to a specific question, ask odd are we know the answer. Another forum you may find useful is
www.bonairetalk.com
One non diving item that you will find useful in helping you pack is a 50 lb digital fishing scale. You can buy these at pretty much any sporting goods/ Walmart type places. Use them to balance and adjust your suitcases so you don't go over the 50 limit and pay the excess baggage charge. I try to keep mine in the 45 lb range to give me a little extra room for t-shirts bought on island and for any wet items that may be adding to the weight of my bags.
Got a 2 week trip planned later this year myself...can't wait to get back.
