Port, Sherry and Madeira - they dominate the fortified wine market, but there are others. Mind you, I'm such a port buff they have to really over perform to get listed!
Fortified wines are wines that have had a spirit, nearly always brandy, added and have a higher alcohol level to table wine. This process was to preserve the wines, and while the three aforementioned wines are the most famous, other fortified wines include Marsala, Vermouth and Rutherglen Muscat. There are also wines from the numerous new world countries that produce their own versions of port.