I have a basic unordered list that isn't displaying in IE8 compatibility mode, but when compatibility mode is turned off it displays correctly.
I discovered the problem. It turned out to be that it doesn't like the background:none property on a list item.
This turns out to be a problem with background:none on a list item. I was doing custom bullets by setting the background image, and on the first item i was just setting it to background none, but this caused the whole list to disappear.