Fallout 3? Fallout fucking 3?
ARE YOU KIDDING ME?
Fallout three's ending (without DLC) is up there with the worst endings of all time. It's about on par with 'rock's fall, everybody dies' of NWN 2. I mean, how on earth could anyone pick this as a good ending for anything? If the ending described how despite your best efforts everyone you had met gained buttock cancer it would be only marginally worse.
I mean, the ending lacked interest and pathos, and worse, made no sense. The game insulted you if you asked your UTTERLY IMMUNE TO RADIATION friend to pull the damn switch for you. That was after they changed the game to make that possible; before that it forced you to do it and auto-killed you, even if, frankly, you were carrying enough anti-rads to survive bathing in fat boy juices. (That would be the water near the bomb in megaton, of course. What were you thinking?)
Oblivion's end was also drosstastic, although to it's (rather marginal) credit, it's ending was only a 'meh' rather than the projectile-vomit inducing FO: 3 ending.
Seriously.
Edit;
Also, while I haven't finished AC 2 or 1, I doubt their endings are good on the grounds that the ending of ACB is god-awful dross that is poorly written, poorly scripted, and annoying to play through. It partially depends of course on where you judge the 'ending' to start from.
Is it just the 'vision'? That is terrible dialogue and involves extreme cut-sceen related annoyance. Plus it involves being desmond, who is the most painfully loathsome character I've been forced to endure being for quite some time. I mean, who the balls enjoys being that guy? His voice is like being punched in the kidneys, and whenever you're being him the game removes all your gear and minimaps and so on because you are at risk of enjoying his eye-bleeding desmondosity.
The last fight as ezio is ok, although the painful 'run exactly this one path through a battle' leading up to it is BS; where's my free running gone, ubisoft?
And depending on where you count the ending as starting, don't get me running on the stupidity that is the whole game post getting the apple. Why isn't fun allowed, huh? WHY I NO FUNZ NO MORe, UBEYSTOFFED?