The live rock that your thinking about is extremely difficult to find today. When you could get live rock out of Florida, it was sold as decorator reef rock. Even then it was expensive.
The closest thing I could find on the net was this (offsite) -
https://www.liverocknreef.com/index.php?l=product_detail&p=7926
The picture looks great, but I have no idea what you'd actually get if you ordered it. I have never dealt with this company and show it only as an example of what to look for. As you can see, it's very expensive.
More typical live rock will be like this (offsite) -
http://www.pacificeastaquaculture.c...-Rock-Special-Shipping-Included-Prodview.html
This rock looks good but doesn't seem to have that much life on it. I have dealt with this company. They are also a sponsor here. I can highly recommend them.
Any rock you get that contains a lot of life will have a certain amount of die off. This means it should be cured in a different container from your main tank.
A lot depends upon what your plans are for the tank. Sometimes it's best just to leave things alone and let anything in your tank over grow the rock. I have has sponges, small tube worms and small brittle stars on my rock. You could also add some good live sand, such as GARF Grunge (offsite) -
http://www.garf.org/!paypal2010/Store.html to help things along. This could be a less expensive option.
If you want stuff like zoas, xenia, or GSP on your rock, a few frags of these can get you started. You'll get real good at fragging them. You can also frag and add most other soft corals.
Lastly, if you are going to order, keep in mind that it is winter, and the cold can wipe out otherwise good live rock or live sand.