Hey Dana of Doom,
My advisor told me to contact POIs as it gets you on their radar. In the best of cases, they ask to see your statement and maybe give you some feedback (This happened to me with Illinois, Texas and Michigan). Some Universities have a policy of not reading anything before the committee meets (this is what I was told at Chicago). Contacting a POI at UPenn got me invited to the campus for an informal interview, while Brown and Indiana gave me some insight on other professors who may be interested in my work. All and all, I'm really glad I did it and I think it has been beneficial to my application.
That said, I'm sure you are not the only person who didn't do it and I can't imagine that it can be held against you if you don't. What I was recommended to do that I think is worth passing on is NOT automatically attaching the statement. Present yourself, talk a bit about your work, and offer to send over your statement if the POI is interested. I thought that was really good advice.