If you're in the mood for drinking and have a long enough layover I would certainly walk over to the Sky Club. The KE lounge has pretty decor but has a pathetic little selection of self-serve alcohol, while the Sky Club has a nice tended bar.

However, there is a particular unlocked door that will lead an intrepid traveler into the KE first-class area where there is always a bottle of 17yo Ballentine's