Depending on the game, the ending usually makes or breaks it for me. I loved Fable 2 so much and then it finished... just like that, with nothing. So now instead of Fable 2 being among my favourite games ever, it's not even in my top 5 RPGs because of how empty and unsatisfied I felt about the end of the game.

Usually when I finish a game and really enjoyed, I get a feeling of accomplishment, a complete satisfaction with the experience and the longing to experience it again. When a game ends badly, it drops in quality for me. The same thing goes for music, books and movies

I personally think good endings are important. An exciting final battle and the how the story finishes may define the way you'll remember the game in the future years.

Of course we love many outstanding games with bad endings and there's nothing wrong about them, but in most of those cases story was not an important aspect of the story. Otherwise, endings can raise the experience or make it flop.

I heard many people complaining that Fallout 3's various endings and yet it one of the most crititcally acclaimed RPGs and it's still loved by many RPG fans.

No as long as the game was good fun to play, that's all tha matters. But Games like MGS 3 and 4 where the endings were just so fantastic and brilliant, that's when they add more experience and very satifying ending to top it all off.

No, great stories make great games.

Good endings are the rewards for a good game.  But at the same time, if it's a very good story-driven game, then the whole experience is the story.  The good ending is just part of what that good story was driving towards.  I admit that MGS3 is my favorite game of all time and the reason for that is the story--and the ending was outstanding.  But I didn't play that game for the ending.  It was the experience as a whole that made me love that game.

I think it's a potentially important piece of the puzzle, but it depends on how a game is constructed.

Super Mario Bros. wouldn't have been so awesome if World 8 wasn't so well-constructed.

No , it's about the journey and little details you'd miss if you just focused on getting to the ending.