I have always pronounced Sauron like 'S-ow-ron', after reading Appendix E of the Lord of the Rings, but now I just listened to this recording of Tolkien reciting the Eagles' Song, and it sounds like he is saying "Saw-ron".
Did I mis-hear it, or did Tolkien do a mistake? Or am I supposed to pronounce it that way, and he wrote "Sauron" so that people would read it as "Sawron"? Highly unlikely, I think . . .