The To-Do List Applet now has a preferences dialog/window, as of r670. You can change the title of the list, which will be displayed when you hover over the applet icon and when you open the dialog. (Not when detached, though) You can also change the color of the icon to:
*one of the Tango Desktop Project colors
*from the current Gtk theme
If you choose custom colors, you can change the outer border, inner border, main color, and text color. You can also choose which type of icon to use:
*standard with number showing number of items
*partial inner border showing progress along with ##% as the number
*both the border of progress and the number of items
I plan on adding a confirmation dialog when you try to delete an item or category ("Are you sure you want to delete this item?"), with a check box next to "Don't show this again." You'll be able to change the showing of that in the preferences dialog.