There are so many dive sites, picking can be hard. I'll lay out what I consider 'signature' sites, that would be good to hit and reasonable in one trip.
1.) Karpata - fairly easy entry/exit, more lush reef than some other sites, one of the favorites of a number of folks.
2.) Ol' Blue/Tolo - fairly easy entry/exit, & a nice reef.
3.) 1,000 Steps - the stair case is scenic, the dive entry/exit easy, and the reef is good. That said, my legs burn coming up those steps.
4.) Oil Slick Leap - maybe a 6 foot or so (guessing) giant stride in, exit by ladder, good reef, and I've seen a number of neat things there. The giant stride entry is one of those 'things to have done' on Bonaire.
5.) Andrea I or II - Andrea II's viz. was worse when I was there in December. The Andreas have pretty good entry/exit access.
6.) The Cliff - basically a fairly shallow roughly vertical wall dive, distinctive for Bonaire's west coast. Figuring out where the entry is from the main road can be hard, though; it's a bit north of Buddy Dive & Captain Don's. Some one else can give a better explanation.
7.) Windsock (not Windsock Resort, although it's good, too, and WannaDive services it so maybe you could use it - ladder entry & exit, pretty nice) - entry & exit are amongst the easiest, and there's a big wooden pier that's useful as a guide for entering & exiting in the same place (this is one of my favorite Bonaire night dives for that reason).
8.) Hilma Hooker - definitely one of the most famous sites. Figure on getting around 80 - 90 feet deep swinging around the wreck, with a few tarpon hanging out on the far side of it.
Those 8 are the ones I'd especially aim to hit if I were new. There are other popular sites; Alice in Wonderland, Angel City, The Invisibles, etc... Aquarius had a nice entry & exit, if you could navigate back to the rather narrow clear channel. If your sea sick wife insists on exiting NOW and taking you with her, you can be crawling over rough rocks to get out...
Speaking of diving a site, here's an option for you. It's common to enter the site, we'll say Oil Slick Leap, notice which way the (usually subtle) current is flowing and swim into it (or just pick a direction, north or south), swim along parallel to the reef/shore, hit a time or PSI you're comfortable with, then turn & come back (perhaps shallower, to off-gas & make your air last longer). You could make each site a 2-tanker; head north on your first dive, south on your second.
Richard.