Look north of Ocala toward Gainsville. Bridgette, who often participates on Trulia works rural, land, etc in that corridor. Perhaps she can chime in here. I definitely suggest his area to begin your search. I am a Broker in Florida and pay close attention to the equestrian and land markets in Florida. Closer to Ocala, land is pricier than it is if you go further toward Gainsville.
I would highly recommend most small towns in Dixie, Gilchrist or Levy Counties. In Levy County you can reasonably acquire acreage only minutes from the gulf. All three of these counties have springs, rivers and wildlife galore. The largest town in the region is Gainesville (in Alachua County), which was voted the #1 city to live in by "Cities Ranked and Rated 2007." Gainesville would be generally anywhere from 30 -90 minutes away depending upon the area you choose. So you pretty much get the best of everything!
You decision lies mostly upon your goals and your intent: Short term or long term? How much acreage? 5, 10,40, 100 acres? What is your budget? Your risk tolerance? I do specialize in land investment (in North Florida, 8+ Counties) and Real Estate Tax (Avoidance-LOL) Strategies. In the "Web Reference" line below there is a direct link to the Dixie/Gilchrist/Levy MLS property search--much of this area is ripe for long-term speculation--check it out! And, of course, drop me an email if I can be of any further assistance. Best of luck and happy hunting!