There's tonnes of speculation, theories, and even spoilers over on the forums imdb.com (I've been staying away from the spoiler threads). imdb.com is a good place to go for discussions on the new and past seasons.
Personally my theory is that the series will have to end with the end of Tony's reign. So that would either mean him going upstate or six feet under (that's another great HBO series). The big question is who would take over? Chris, Paulie, AJ, or even Meadow?? Meadow might seem like a stretch but who knows, it could be possible and would be an interesting angle.
P.S. I think a movie version would be lame, and I believe the idea has already been discussed and shot down.
Last edited by hugh; 2006-03-12 at 03:41 PM.