Rather clearly it does matter what state you are in. In Florida, a lease of less than 6 months is considered to be the same as a hotel stay and is subject to hotel tax. A lease of 6 to 12 months falls under the protection of the Florida Landlord/Tennat Act (see: http://www.800helpfla.com/landlord_text.html). A lease of more than 12 months is considered a commercial contract and in theory should be drawn up by an attorney. When I do rental I always advise my clients NEVER to sign a lease of more than 12 months in Florida. If you want a longer term then consider signing back to back leases of 12 months or less.
Of course, I must say I am not an attorney, so this isn't legal advice!