I've been a kayaker for several years but hate fishing. I do however love to spearfish with spearguns. We live on the gulf and are avid scuba divers and snorkelers, down here we take our fins and snorkels and sometimes dive tanks (and spear gun of course in legal areas) out with us whenever we go out. We also have a place down in Key West where you simply jump overboard pretty much anywhere you like and have fun (year round).
Now the bad news, the ocean is very large and often wind and currents can change quickly. Very seldom is there any interesting stuff right near shore (just alot of sand). When we go out we are often out all day and a good day for us is 20-30 miles (we like to island hop down there but you need to be aware of the spear fishing protected areas).
We started with an Oasis and a Revolution (both really nice boats) but didn't feel comfortable taking them into open water or travel any great distance from launch. We purchased a Tandem Island in spring 2010 and just love it. My wife and I can load all of our diving gear on board with a couple tanks each and just go out and enjoy the day. The main propulsion is the sail of course when there is enough wind but even with light or no winds we can pedal lightly and get where we want to go. Both of us can pedal 10 hours in a day, then get up and do it again the next day. The beauty of these boats is if your legs get tired, just paddle for a while, and if the wind picks up give your legs and arms a rest and sail a bit (simplest boat in the world to sail, no experience needed, you just unfurl the sail when you want to sail, and furl it back in when you want to peddle (only takes 2 seconds)). You would be amazed at how much this extends your possible range. With two people it's not so lonely, and you have plenty of room with the trampolines to store coolers, food, and the fish you caught. We even have a big bimini that we put up when were diving so we can get out of the sun when diving or just chillin. During crab season we stack 10 crab traps on the trampolines and go out and place our traps.
I honestly have never owned a more versatile boat. When we first started kayaking we would rent paddle kayaks and maybe go 3-4 miles and never venture more than a few hundred feet from shore. We moved up to the Oasis and revolution and tripled the distance we were comfortable. When we moved up to the TI we tripled the distance (and fun) again.
What I suggest is you go out and buy a used Ocean, Wilderness or Tarpon rotomolded SOT kayak. They don't hold their value at all and you can easily pick up a 2-3 yr old kayak for a couple hundred bucks (or free because people just want to get rid of them, especially in Florida). Use it for a while and make sure you are going to continue to use it. Then if still interested, upgrade to a Hobie revolution (or Oasis if there are two of you). Use that for a yr or two and if your still really into this stuff sell or trade it in for an Adventure Island or Tandem Island. Hobies hold there value better than anything else out there, and when the time comes (if you take care of it) you should be able to sell it in a few days for almost what you paid for it (used Hobies are very rare). I bought my revo 3 yrs ago for $1800 and sold it recently for $1700 ( sold in 1 day). We traded our 2008 Oasis into the dealer when we bought our TI (we got $1800 for it).
We actually have more fun with the TI than we ever had with our SeaRay powerboat (costs $60k plus $300/month for dry storage, plus 2k/yr for maint, and about $40-$50 per week fuel) verses our TI (cost $5000, storage zero (we keep it in the garage), maint (next to nothing), fuel about $10 dollars total since we bought the boat ( I have an emergency gas motor on the boat but have only used it 3 or 4 times in the last 1200 or so miles since we go offshore mostly I never go out without it (for safety reasons).
Another cool thing is whenever we travel we always just throw the Kayaks up on the roof, and if we see a fun place we just launch from along side the road or any park or beach. Especially on the way to Key West, you can put in almost anyplace along the route.
Hope this helps you