I posted a few weeks back on Stephanie Posavec's interesting graphics constructed from the text of Kerouacís On the Road. One of her pieces featured Sentence Drawings that were generated using each sentence in sequence with line segments coloured to reflect the topic and sized based on the length of the sentence.
David Spark's Sentence Drawing for SOTU 2008 (click to see graphic with all 8 addresses delivered by Bush)
I find these interesting to look at. However, the dominant visual feature is the overall shape of the graphic and I don't think it really expresses anything useful.