Everything Better Than Everything Else

I think it's fair game to consider this in terms of incarnations - if so, the first three Wire albums could qualify although they're all great.
and with the potential quibbling over faves, maybe it's easier to look at whether an artist/band keeps evolving (in a good way), in which case Japan (above) fits the bill better than most. they certainly went out on a peak of interest/exposure.

a couple of incarnations that might work are:
Van Der Graaf Generator first incarnation up through Pawn Hearts.
Roxy Music second incarnation Manifesto -> Avalon, at least in the sense of refinement.