I'd echo that. Nate was very helpful when I was writing mine last year...from my experience talking to people in admissions, something they really want to see is why you're interested in their school. What you think you can bring to their department, and what they can help you with.
I started mine with a bit of background...how I wound up in my field, some of my fav. courses, other experiences (internships, etc) related to the field, etc. Then I talked about ultimately what I wanted to do with the degree, where I saw myself working. Then I talked about the school - what I liked about it, specifically what courses I wanted to take, any opportunities (concentrations, internship programs) etc they had that interested me, that sort of thing. I tried to make this section very specific to each school. I addressed why I thought I was a good match for their program - why my skills and background would help me succeed. Also any qualitative factors - did I like the area? Did I like the people I'd met there? that sort of thing.
I also tried to include some details about who I am as a person...outside hobbies, etc, because I figured they already have my transcripts, my application, they know a lot of "facts" about me, but it's a good chance to make a memorable impression. It's the one spot where you get to argue why you think you should get the spot over someone else
Anyway, best of luck! I'd be happy to read them over for you if you would like.