jharker, you beat me to the punch.
I was just going to ask for the same thing, along with a request to have slightly smaller bookmark entries (not so tall) to allow for more per page.
I've just started doing some course work again, and I've been using the bookmarks feature. I'm starting to wonder how I managed without it last time. It's not so relevant for reading fiction I suppose, but for other contexts I can see it becoming indispensible.
Scribbled bookmark descriptions would be great!