Devil's Den is good - a much better dive than Blue Grotto IMO. It's not so much the dive at BG that I don't like as it is the price gouging that goes on there.
Ginnie I find to be boring (The Ballroom at any rate). But if you've never done it then you have to do it at least once. I would like to go back for the Ear and Eye (you have to hold at least a Cavern cert), but I'll pass on the Ballroom.
Paradise Springs is a good one. They allow OW, but really to get the full dive you need to at least be Cavern. It can be very silty, as with any of the other dives mentioned, but this one especially because of the sharp angle at which the cavern descends. It's about 45 degrees all the way down.
Hudson Grotto (I can hear the groans) is a good one too. Most people don't like it because the water is very tannic. It basically becomes a night dive below 40ft. It's an excellent place to test gear out and it's very cheap ($15). They've got a lot to look at it down there if you take the time to try it.
There is also Hospital Hole which is a large sink in the Weeki Wachee river. You'll need a boat to get there but most dive shops run trips there when the weather is good. The Hole is usually always full of manatees and other wild life that seek refuge from the colder waters during the winter (it's spring fed). You can rent a canoe and get there yourself. It's only a short trip from the nearest park (Roger's Park).
As for shops - I pretty much stick to Diver's Supply. Scuba West isn't bad either but I've had only limited exposure to that shop.
