In 2008 the advantage was 657,775
http://election.dos.state.fl.us/voter-registration/statistics/elections.shtml#2012
In 2008 Obama won Florida by about 240,000 voters. Everything else being equal he can win Florida by about 100,000-120,000 votes. That''s all that counts. You don't get extra electoral votes for winning by larger margins.
In the final day they removed 3,906 Republicans and 5,306 Democrats from the voter rolls.
Voter Registration as of: 10/25/2012 Republican: 4,249,897 Democrat: 4,787,284 Other: 2,913,368
10/26 Rep: 4,245,991 Dem: 4,781,978