Minor suggested tweak - maybe when you have messages, make the text (or at least the unread message count) a slightly more high-contrast colour, like yellow or red, so it catches your attention more easily. Alternatively, to avoid stuffing up the colour scheme, a small and subtle animated .gif, such as a rotating bullet point or something, could be a good signal.
I found I only checked it because I read this thread, and found there were a couple of messages there.
