The Antipodean

What about The Wizard Of Oz (1939) and Return To Oz (1985) = 46 years. Obviously not the same actors, seeing as Judy Garland was, y'know, dead and all, but very much the same storyline (based on the original books) and at the time pretty much marketed as a sequel and bombing horribly because everyone expected singing and lightness instead of (IMHO) a much more effective adaptation of the original books.

danol

Eddie and the Cruisers 1983 sequel Eddie Lives 1989.

Giantrobo

2001 and 2010 had nice stretch

DRG

Next summer's Re-birth of a Nation reunites most of the original cast, but it's having difficulty finding a distributor due to its controversial nature.

NCMojo

Speaking of Re-births... what is the deal with these resurrected threads? Someone has been digging around in the history books.

MasterCXtreme

ummmmmm Star Wars maybe? Suprised nobody has said anything so far. Sure Episode 1 is a prequel, but it's still pretty far apart from "Return..." I don't know the years so I can't do the math.

Groucho

There was 16 years between Return of the Jedi and The Phantom Menace, which is a lot but not even close to some of the other entries.