As ever, though, you are strongly recommended to speak to a professional tax guy (rather than a Realtor) when you get into this more complex stuff. As a UK accountant, I can honestly say that I use a CPA for US tax advice, just because of the sheer befuddlement of the US tax system.
Property taxes are more if you are a non-Homesteaded property owner. If the home becomes your primary residence, then you can benefit from the Homestead exemption. If you already have a primary home then you would be taxed on a non-Homestead exemption, as would anyone in the United States or Foreign countries. Taxes are based on millage rates for each city/town per assessed values by our County Tax Collectors.
The tax you might be thinking of is the Foreign Investor Tax which is charged if you own a property in the U.S. and sell it, but you do not have a Social Security number in the U.S., this is a 10% tax based on the purchase price which is paid to the IRS. If you need more information, I will be happy to provide this for you. You would be considered a Foreign Investor and subject to this 10% tax, only when you sell.
Broker Bryant has hit the nail on the head.
Also, Florida passed a law that counties can't raise taxes on your home more than 10% a year.