You just asked the Million dollar question!!!!!!!!!!!
IMHO, the absolutely, very, definite, best lounge in WDW is Victoria Falls at the AKL. It's right off the lobby. the wonderful exotic aromas from Boma and Jiko drift up to tickle your sense of smell, the babbling of the brook and falls provide a soothing background noise, and the inspired lighting designs provides enough to make it comfortable, yet not so much as to ruin the intimacy.
Wish I was there right now...
Anne