One thing I run into time and time again is a list of things that are interactive. WAI-ARIA does have a role="list", however, ,it is defined as a "list of static elements". Most notably, this means screen readers do not enter forms/interactive mode when encountered. The examples I"m thinking of don't fall into any other category- they are not toolbars or menus, etc...and I would like to avoid role="application" (since that's not what it is either really).
1. A inbox list (a list of e-mail messages)
2. A list of attachments in an email (or any list of links you would like to navigate via arrow keys rather than tab, but don't fall into the category of a toolbar or menubar or foldertree)
3. A list of messages in a thread (a la gmail)
I know there are more, but that is all I can think of offhand. It's the #1 issue I have when working with wai-aria and email clients...