I have visited so many, I wouldn't even venture to count them. Most of them have been Maine. I have been to the usual ones, Portland Head, Bass Harbor Head, and West Quoddy Head (the eastern most point in the continental U.S.) and many others that aren't frequented as often by tourists. I have been to lighthouses as far north as Prince Edward Island and as far south as the California Lighthouse in Aruba. I have been to lighthouses on the Great Lakes (Presque Isle Lighthouse in Erie, PA) and as far west as Hawaii.
My favorite lighthouse is Bass Harbor Head Lighthouse on Mount Desert Island in Maine, near Acadia National Park. (See the attached photo).
While you can sleep in one of the lighthouses on PEI, my wife and I would love to live in one. If you'd visit, 'we'd leave the light on for you.' ;-)