I tend to get very dry lips, especially on the 777, and have found the Elizabeth Arden 8 Hour Cream lip balm to be the best. Not cheap by any means, however definitely worth it for me.
We sell an Elizabeth Arden set on the aircraft which costs less than the lip balm alone, plus our crew discount makes it a lot cheaper. It is also a lot cheaper in the US and Canada if you happen to get there.
The comments about water are indeed true. I am always drinking water onboard.