I have been to Bonaire 11 times in the last 5 years. Have also gone in all seasons. Summer is the best for fish life. The rest of the year is pretty good.
Dove 10 days after Omar and noticed that some sites were hit harder than others. Karpata look untouched. But lots of loose sand. By Christmas diving in most places had improved, with Oil Slick and Witch's Hut being noticeable exceptions. In March the overall visibility was poorer than at Christmas. But the fish life was tremendous. Huge bait balls, chromis all over the place, jacks and porgy's, and more groupers than I have ever seen. The hurricane also helped the Moray eel population overcome a general bacterial infection problem.
I have a trip planned for October, 2009 and starting to put a plan together for Christmas.
If you can walk with your gear on, you can find 20 dive sites in Bonaire that you can dive with no problem. Easiest is Tori's Reef after Omar. If you can walk 20 feet with your gear and fall down, you can dive this site. I know of no easier dive entry or exit anywhere else.
Rented trucks every time. Have had no problem with crime. Roll down the windows in the morning and leave them down to the end of the day. Roll them up at night so that the rain will not make the seat wetter and colder than necessary. Leave the doors unlocked. On dives, we load up with tanks, at least 2 per person. At the dive site we have had no problem with leaving shoes, t-shirts, towels, water, food in cheap coolers, mesh dive gear bags, weights, weight belts, maps, hats, sunglasses, and other stuff that we like to use but if someone needs to steal it, they can have it. Have done this on dives all over the island and at all times of day. Never had anything stole. Though there were several pairs of shoes that we wish were stolen.
I have been to 4 different resorts and they have all been good. Security at all of them and no problems with losing gear.
I hope that this is helpful. I really like diving Bonaire. Of course I like to ice dive and river dive in December in 32 degree water, so I may not be the best judge.