Thanks!  I was really happy with how this cycle turned out for me considering I didn't have anyone advising me and I apparently did everything "wrong" according to the conventional wisdom.  (I only applied to three schools, among other things...)  And you're right, a personal visit almost certainly does have more weight than an email exchange, but at least in my case, none of the professors I contacted seemed to think I was a pest for my initial emails or wanting to sit down with them, which really you could argue was even more of an intrusion into their time than just exchanging a few emails.  My guess would be that it probably does depend a lot on the professor.  Dr. Athey is clearly not a fan!  But I don't think that means it's always (or almost always) a bad idea.