I agree with Orbert, but get Going For The One before anything, because I feel it is the most accessible of those three albums.
And Tales is really hard to get into, but once you do, you will be blown away. I suggest starting off by taking it one song at a time (I went Ritual, then Revealing Science, then The Remembering and The Ancient). I feel that Revealing Science is the best song on the album, and perhaps my favorite Yes song.