My personal fav is still the Malaysia Airlines' Golden Lounge in Kuala Lumpur International Airport. I find the large expanse of space very soothing and its the reason why I fly Golden Club Class whenever I can, so that I can use the lounge. I still have not encountered another lounge that comes close to it. Despite the size, the Golden Club section gets very crowded in the evenings. However the First Class side has a "tolerable amount of people.
I like the rerstaurant where you can sit down to a meal amidst a full dining setup. Unlike the rest of the lounges I encountered where you have a small plate and eat at your little corner you conquered.
The entrance to the lounge is simply awesome as well. One word describes it - elegant! Wooden finishes, shallow pools, marble flooring and a bright reception... I am looking forward to the next trip.
By the way, it is the largest airline lounge in the world!
I would like to try Cathay Pacific's lounge in Hongkong because I have heard so much about it. But not before they lower the J Class fares!