Here's the ones I know by heart that first come to mind: 1)The Scene where Cal gives the gun to Lovejoy and says if he can get the diamond he can keep it, Jack ends up kicking his freaking butt; that's why you see Lovejoy all bloody when he is leaning against the rail when Titanic splits and he dies.
2) The Scene where Jack and Rose see a shooting star while coming back from 3rd class party. I personally think they should have left this in because it's a sweet scene and the last line that Rose says before saying bye is "Something I can't have".
3) When Rose and Jack kiss in the boiler room. :D
I know quite a few. They include: The Jack/Lovejoy fight in the sinking dining room, the wireless guys abandoning their post, Guggenheim and JJ Astor saying farewell, Cora's death, Jack telling a guy in the water to stay away from the big door Rose's floating on, the extended scene of the Carpathia's rescue, the shooting star, breaking into first class, being the first, Roses' freakout, and some others...