I have a good friend who lives in NPR and have been there several times. There are numerous (so I hear) MTB trails in the Tampa area. Do a couple google searches for "tampa mountain biking" and you'll find links to the local MTB clubs.
From a living stand point, it's a pretty nice area. It is a Tampa suburb, with everything available nearby. The area has grown exponentially, but there's still some countryside to be found.
As for road biking, it's probably OK, but watch out for 1) old folks and 2) rednecks. There's lots of both on the roads; the elderly simply won't see you and the rednecks want to scare you. Traffic is at it's worse in the winter when all the snowbirds come down.
It's Florida. No hills, except for overpasses. There's some "bumps" that run down the center of the state, as well as some small hills in the old phosphate mines which have been converted to into MTB trails.
Dave
(currently freezing my butt off in Baltimore)