To make use of more screen real estate for people who use widescreen, make a to-do list available on the left hand side of the screen. Just a simple paper style list that you can add text into.
Oooo . . . I like this idea A LOT! It could be collapsable. Both it and chat could have adjustable widths (think Outlook calendar and task list). I have a lot of unused real estate on my main PC.