I think Seventh Seal is one of the weaker ones from him, i didn't like it all that much, i even prefer Virgin Spring to it, when it comes to his costume stuff.
Through a Glass Darkly, The Silence, Cries and Whispers, Fanny & Alexander (full version though) and Scenes from a Marriage (also full version, plus Sarabande) are probably my top choices, off the top of my head.
Echo i'd start with Wild Strawberries and go from there, but i'd leave Persona for later on, since it's bit more abstract, compared to his other stuff.