Just finished the graphic novel - I got it signed, too - and I'm reeling a little. The story is expertly revised for illustration and the art is gorgeous, so it accomplishes just what the movie did 25 years ago.
It's incidentally 40 years since the book was published. The author apparently wrote it when he was 24. That's what hurts. I don't know exactly why. Maybe because I couldn't write like this if I lived to be a thousand; maybe because knowing that is almost exactly what the book itself is about.
There is nothing in the world that I can recommend like The Last Unicorn. If you haven't read, read, if you haven't watched, watch. If you've done both and you still need more, the graphic novel is published by IDW and entirely worth it.