There's a variety of thoughts on when a game ends, but I have to agree that most experiences end when the story comes to a finish. I've found that the really great games go beyond that, however. Games like Super Mario Galaxy finish the story about halfway through the initial play experience, but the fun and challenge will take you much further if you let it.
Speaking of Super Mario Galaxy, now that it's out in most major markets (just a few more days, Australia!) the time has come to ask whether or not it's met your expectations. Was it everything you hoped it to be? Did it surprise you? I feel like I'm asking the gaming version of Stephen Colbert's "great president or greatest president" question, but I'm curious on how you all feel the game stands now that it walks among us.