The ABC's - more specifically Bonaire or Curacao
Either one has more shorediving than Cayman. By several hundred percent. Both are setup to do mostly that. It's so popular on Bonaire that the rental trucks have tank racks in the back.
Both are more reasonable also. Bonaire's quieter than GC, Curacao's bigger. You can either stay right on the water and shoredive from your property or stay a short distance inland - blocks to miles - and save on accommodations. fwiw Cayman was the most expensive place I've ever stayed in the Caribbean, Bonaire was maybe 4th.
Most days the water is as good or better than Cayman on Bonaire since there's no natural runoff and it's been a Marine Park for decades. Curacao can be a little cloudier in some areas but the West End is still supposed to be as good. I'll let you know, we're there in April.
One thing you won't see as much of on Bonaire is big stuff. There's Tarpon, some Turtles - but mostly off Klein Bonaire which requires a boat - and we saw the occasional small ray. There's dolphins in the channel between the two islands but we've never been lucky enough to see them while diving. Tradeoff is the smaller stuff is abundant, thousands of fish and soft corals, the occasional frogfish, sea horses, squid etc.
Personally I think the coral in either place is as good, Cayman has better formations in some areas but I've been on whole dives off Bonaire where I couldn't find a sandy patch except for close to shore. Part of the reason you do a buoyancy check dive when you get there, there's no place to land.
We did our trips to Cayman and Bonaire in 03-04' so it's easy for me to compare.
Boatdiving is cheaper on Bonaire also, we did a 1-tank in the afternoon once for $18pp. Just us and another couple, four was all Toucan needed to send the boat. If you buy a package deal there, a lot of the diveops throw in free shorediving on those days.
Or you can get free shorediving only all week for $110-120. And you've never seen a place so set up for it, at Buddy Dive they even have drive-thru tank exchange. Most of the diveshops have similar arrangements with local properties. Four dives per day was our average not counting night dives.
http://www.scubaboard.com/forumdisplay.php?f=562 or
www.bonairetalk.com for more info.
