When I was a kid, I used to beat single player campaigns multiple times. I beat RE4 about 10 times. But now, I'm usually just happy beating a game once. Some games I do replay (and it has nothing to do with it being better than the others).
For example, Half-Life 2 and A Link to the Past, I see as two of the best games I've every played, yet I only played through them once and no more. I may try them (and others) out 5 to 10 years from now, but for now, I want to finish games on my backlogue before I start new ones.