Utena is just indescribably great... except for one thing.
The stock footage makes it horrendously tedious to marathon.
Now, you have to understand, the producers of Utena were heavily limited by budget, and all that stock animation is there to fill gaps so the rest of the show could exist.
Other than that, I can't think of a show with as many memorable episodes save Cowboy Bebop. It's fantastically written, with gorgeous music and rewards multiple viewings very generously. I'd give it my highest recommendation.