+1 for Curacao - they have 40+ shore dives, all easy beach entries. They also have the
DiveBus - for around $100 they'll take you on two escorted shore dives at some of the better dive sites to get familiarized with the process before you go out on your own. The advantage Curacao has over Bonaire is much simpler entries. At either the reef parallels the shore and it's low to no-current diving generally.
Tanks for shore dive rentals are $7-10 so all you need is a car. Boat dives seem to be around 2/$100 - you should do some of those as there are sites not shore acccessible.
Also just about every dive site has an on-site operator and refreshments. It's on the same reef as Bonaire just 50mi. away so you'll see almost the identical things. Should you want to do a special dive for your anniversary, for $200pp. you can
dive with the Dolphins at the Seaquarium/Ocean Encounters. It's done on a shallow reef so entry level divers can do it. OE is also one of the safer operators on Curacao. You will need a car as the dive sites are spread out along the coast.
Many of the entries on Bonaire are over ironshore and coral rubble. It makes being sure-footed with all your gear on your back a lot trickier. Outside of the dive resorts in town, no shore dive on Bonaire has any facilities and some are pretty isolated. See the differences in the site photos here - the brown stuff just outside the surf line in the Bonaire photos is the ironshore you have to climb over to get out to the reef. Since the reef starts further out on Curacao, it's a non-issue there.
http://www.shorediving.com/Earth/ABC/index.htm
Curacao has many good restaurants, nightlife, casinos, and most dive sites are on excellent beaches. World famous shopping district downtown. Most of the people live in/near town so farther west is a lot more isolated - at several dive sites we were the only divers for several hours. A lot of the beaches are locals beaches so there's usually someone around besides the dive operator/concession operations.
From Newark it's one stop - 8hrs. total flight time both ways. Under $600 r/t late spring.
For your budget, the Marriott Emerald Bay in the Piscadera Bay/Beach area would be on my short list. [-]Rooms[/-] - Suites are about $400/nt. There's a decent shore dive off their property and Caribbean Sea Sports on-site for both boat and shore dive needs. The Hilton next door is very old and disappointing.
Curacao Travel- Caribbean, Curacao, Dutch Caribbean lists everything you need to know. A lot of this is discussed repeatedly in the Lesser Antilles sub-forum. Most things Bonaire -
www.infobonaire.com