I'd keep absolutely nothing, not even the things I like. I'd have the whole thing redone from scratch.

It be hard to make a decent remake of the original trilogy, because they have always been such well known and famous movies, but rather than make another SE of them, I'd say go ahead and make an entirely new saga from the start on. The originals would still be around and entirely untouched, I'd rather have my guys do a remake than glue bits and pieces onto old films to try and make them look new.