Vacation Packages

Groupon Getaways - these are fantastic if you can travel off season or on specific dates.

Travel Zoo - while these prices are very low, there's a huge catch.  You have to go on their organize excursions or they'll cancel your return flight home. They great part is you get to see some amazing sites!  The problem is you get 1 hour at the destination and 3 hours in a shopping mall of their choice.

CheapCaribbean.com, BookIt.com, etc. - I do not particularly recommend any of these.  They are not getting you any better of a deal than you can get yourself by purchasing directly through the airline/hotel.