Persona is brilliant, one of the best movies ever. Unfortunately, I watched a cruddy VHS; I'm sure I would've liked it even more had I seen a decent transfer with legible subtitles.
I saw Nattvardsgästerna (Winter Light) a while back, and it wasn't that good. Boring and depressing par-for-the-course examination of God's presence in life. A better film though is Det Sjunde Inseglet (The Seventh Seal). The knight plays chess with Death. Love it. And "Death bids them dance." One of the best endings ever. Still, the transfer on this sufferend as well, as did the subs. So I'll need to see it again, too. I also need to see Smultronstället (Wild Strawberries) because I've heard it was good. And Cries and Whispers. All his films are very slow, though, so you have to be in the mood.