It's a matter of taste, as always. There's content mutual exclusive to both versions, the director's cut doesn't include everything from the original and vice versa. I tell you what I did. I chose the original first, because it includes the classic intro, that lots of people love and as I've never played BS before I wanted to get the original feeling which made the game famous. After I've finished the game, I immediately started the Director's cut. It starts different and you get the nice extra story that is added. The original parts are very similar, so you can play them through very quickly, as you still know all the puzzles. This way you get both, the original feeling and content, plus the add-ons of the director's cut. This works very well, because the Director's cut adds rather a different perspective than just additional content to the original scenes, which you can rush through.