That's the big debate down here in the Orlando-Tampa corridor. Right now, only reasonable path is I-4, which despite being 3-4 lanes in both directions is often a parking lot for sometimes hours on end for about a 50 mile drive. State and counties been bouncing back and forth on it.
I say, like most people I think, that we really do need it. But, the reality is that unless it is done such that there are easy options for public transportation springing off of it then no one will use it.
Unless you work right next to a station, you're screwed. And the area is so spread out that everyone needs a car to be able to pick up laundry, go to the grocery, run errands, etc.
They put in light rail in South Florida, from West Palm to Miami. On game days at Joe Robbie Stadium they get decent ridership because people can leave their cars in West Palm, spare themselves the white knuckle drive on I-95 or the turnpike with all of the uninsured lunatics out there, and save a lot on parking at the stadium.
Otherwise, when the train passes, you sit there and watch empty car after empty car go on by.