Whichever has the best soundtrack.

Having watched both, the 1943 version is the better Titanic movie, which isn't difficult, since the 1997 version is a chick flick that happens to take place on the Titanic. The 1943 version is about the circumstances leading towards the tragic end and portrays the stories of many different characters.

Amusingly, the 1997 version stole a part from the 1943 one, where some guy named Bobby is arrested for fighting and has to be rescued by his friends during the part water flows into the ship by breaking open a door.