The left navigation is *really* busy. The images on the navigation graphics make each button appear stuffed full of things. I'd like to see that more simplified.
The black background on the left and middle columns when they run out of content looks like a mistake. Maybe faux columns
would cure this.
I like the photo treatment a lot. And the fact that they are randomized on reload is a nice touch. You've got a lot of announcements and, for a school site, that's important! The "posted on" dates are a subtle indication that the site is updated frequently, another important trait of a school site. Try to make those pop ups a little better, though:
How fast does this page load over a 56k connection? Is that a concern for your community?