I'd like to add "The Leading Hotels of the World".

It's a bigger status in Europe than in the US, but they have to be high ranked in several qualities to be considered a "leading hotel".

www.lhw.com

There is also a new one opening in Munich next month which we're staying at in January.

Perk-not sure about other airlines, but Skymiles are earned through www.lhw.com/skymiles