I recently tried to book a 3 leg flight to Europe through Kayak.com but ran into problems and contacted Lufthansa directly by phone. Not only did I get the same deal as Kayak, but it was much easier. The flight was GREAT. Comfortable seat, good food, free wine and excellent flight attendants. It made the long 11 hours on a plane pass easily.
The only reason I'm not giving 5 stars is my flight home. Since they do not offer a direct flight from London to Los Angeles they put me on a flight "operated by" United Airlines which I didn't realize until I got the conformation email. United flights are never as good as Lufthansa flights.