http://www.zillow.com/

"Free Instant Valuations and Data for 60,000,000+ Homes (...and you don't have to enter any personal data info and no one will contact you)"

Kind of surprising they're got numbers for Okaloosa and Walton Counties since those kinds of web sites sometimes ignore smaller markets, but I guess the tax collectors here make it easy to get their data files.

Nifty and fun web site, though it's still described as being in beta. Their values for homes in my neighborhood were pretty consistent with what houses have been really selling for, but their numbers for my parents' home in MI were way off, possibly because of incomplete data sets.