Take a look here first. All lighthouses known to offer guest accommodations - We could not resist this one. For those who like the ocean on the door step, it won't come much closer than this. Some great locations mostly in the USA but one or two in Europe too. Net Hotels - Lots of choice here in this easy to navigate site.
Hotels are listed in state or country format, many carry detailed reviews.
A number of hotels also offer Special Deals. All in all a good starting point. HotelGuide - Hotel Guide lists over 60,000 hotels around the world, including accommodations of all types and all levels of luxury. Search the convenient database to check daily rates, facilities, and more. A good site with plenty of choice.