I think it depends a lot on the length and the tone of the story. A shorter novel might have a final chapter for resolution and be fine. A detective novel where all you're really learning about it the investigative process could get away with a very short resolution - the process is what you care about and it ended when the crime was solved.
A multi-volume story can have several chapters and be just fine - the LoTR has been mentioned, the Belgariad is another one that comes to mind where you've 'watched' the characters grow for several years (their years anyway) and it seems appropriate to devote more time to what happens to them in the 'happily ever after'.
If the Wheel of Time ends too quickly after the climax, after over twenty years of reading, I for one will be sorely disgruntled.
