I second NOAA charts. They are the official chart provider for US waters and are free to download. When you download from NOAA, you get a corrected and up to date chart. You have to download weekly if you want your charts to be
current. You can also check out NGA. The
Navy uses NGA charts and are free to download for US waters. NOAA charts are better though. For larger scale charts in the
Bahamas, you might have to
purchase from somewhere.
Bluewater Books in
Fort Lauderdale should be able to point you in the right direction.