I think I would say:

Asia: Hong Kong hands down. Tokyo did not have many options until relatively recently (I remember the times when you were really looking at the Park Hyatt, Imperial, Okura, and then maybe the FS Chinzan So and the Seiyo Ginza as options). Arguments could perhaps be made for Bangkok (primarily based on value). Beijing, Shanghai, Seoul, KL, Singapore still behind.

North America: I think it would only be NY, though I say that begrudgingly.

Europe: London and Paris.

All around winner: probably Hong Kong, actually, taking overall service into account.