I would love to see The Sopranos continue on for quite awhile. It's my fav TV show of all time, but still I do think yeah maybe it's time to end it especially after season 4 which kind of stunk compared to the first 3 seasons.

Plus like someone eluded to earlier, you want to go out on top. Like M*A*S*H did when it finally went off the air. The show was still on or near the top went it ended it's run, and people still remember it fondly.