Hm...I don't know.
In every case where I have contacted a professor it was because, ultimately, I was planning on wrangling an in-person interview. These interviews certainly helped me as I was accepted at all the schools I visited (Yale, Princeton, Berkeley, and Chicago).
In any case, I should currently be a PhD student at one of those schools in modern art, but I declined in order to take a righteously awesome fullbright grant to study in the Berlin Bauhaus archive over the past year. And now am reapplying. I didn't take a deferral last April because I wasn't sure how my field of interest would change over the course of the year... In all honesty, I'm not obsessed with the Yale/Harvard/Berkeley/Blah blah blah. There's so much more to a department than a name, and as I think I am more advanced in my studies than most, my biggest concerns are supportive faculty and good funding. Those are both hard to find.
Anyways, this year, I've applied to: Penn, Chicago, Northwestern, Yale, Duke, Princeton, and WUSTL. I just submitted all of my applications today, now, let the wait begin.