depends on the game. It's nice to feel the accomplishment of completion, but there can definately be a let down knowing that the fun is over. Novels can be that way as well.

I beated Assassin's Creed. The game was great and all but I wasn't sad when I beated it because the game was great but also unforgivingly repetitive .

I'm usually really exited and start playing through a second time. Then I will get a new game or go back to an older game about halfway through my second play through.

depend on the ending and how time i have put into the game

Sometimes but my saddest moment and must triumphant was not a complete game but one puzzle in a game. This won't mean much to you youngsters but back in the dark ages a company call Infocom did these fantastic text only games. LOL, I guess you could say they were the first HD games if you had a good enough imagination.

In the Hitchhiker’s Guide to the Galaxy they had an incredibly tough puzzle to get the Babel Fish, to put in your ear so you knew what the aliens were saying. The puzzle was multilayered and I kept finding that I needed things that I hadn't picked up earlier in the game, so I went back to get them. Finally after spending a few weeks, thinking I had solved it, only to find another layer; the final part was I had to pick up the junk mail on my porch at the very beginning of the game.

When I finally solved it I stood up and applauded the computer and knowing it would be anticlimactic, I never finished the game. I also felt a little sad because I was sure I would never see as good a puzzle again......and I never have.

Baten Kaitos Origins was not epic. It was pretty boring. So much so that I stopped playing probably 1/3 into the game...

The only reason I finished Tales of Symphonia was because I literally got to just before the final boss before getting completely bored with it so I decided to take 30 minutes and finish it because I was already right there. ^_^

On-Topic:  Yes.  Skies of Arcadia recently was this way for me.  I went around doing just about everything I could before finishing.  The game was just plain fun.  The only things left to get involve a couple hours of grinding so I decided to pass and finish it. 

Yeah because I know that the surprise and the magic of the game won't be the same again. But I just can't leave a game unfinished so got to do it huh?

Yes, I do.

Mass Effect is the best example for me. God, the ending was just too epic, especially when you have invested a couple of months in the game (school was killing me). I always thought "Oh, this is how it all ends? Hmmm, ok..." but then another fight starts and another cutscene appears, etc. Let's just say I haven't been so proud to watch the credits of a game in my entire life (and the music was pretty good, it matched the style)! I was sad at the same time because I would have to wait another year for a sequel.

Oh yeah, I also recently finished Grand Theft Auto IV. I didn't know if I wanted to complete all the side-quests (stupid pigeons...!) or just finish the game already (the last missions were intense... emotionally as well? ;) ). Usually, I try to keep as much side-quests as possible before beating a game so that when I finish it, I'll eventually come back and try to complete it 100%... but I couldn't help myself this time! I'm a bit sad now because I wished I would have done that. Socializing sucks! =P

I have to say that Metroid Prime 3: Corruption was an important title for me as well. I mean, I've played through Metroid Prime and Metroid Prime 2: Echoes just for that game (and can compare all of them in the end too, so it's fun!). I didn't want the game to end though... God, I just can't imagine when Metal Gear Solid 4 is going to come out! I don't want to see Snake die! @_@

Since i love adventure games, i'm very sad when a grat adventure ends. On the other side, i'm eager to see what's next in the story as fast as possible. So, it's some kind of love-hate situation :)

Same goes for books. I can't wait when the next story in the Miles Vorkosigan saga hits the shelves...

I cried when I beat ToS...Then I beat 4 more times........I still miss it I'm going to start another file over the summer D: