Currently these are the priorities I've noticed regarding UI topics on irc, d.o and lately g.d.o:
- User menus have a create content folder (which is confusing for new site builders) instead of having direct create content links
- Admin and site manager menus being difficult to navigate
- Node forms (add and edit content)
- Views 2 UI (I only started using Views 1 a few weeks back so it might take a while to get a Views 2 UI wireframe ready. There seems to be a lot of talk about a Views 2 UI re-work on IRC.)
I don't think I'd be able to find out every possible UI issue floating around d.o or g.d.o so if there are any UI issues regarding core or contributed modules please comment or even better make a story about them. Having one specialized usability group tackle UI issues can be very effective.
Is it possible to allow non subscribers to post to comments on this group on a thread (blog order of posts with the latest request on top,) for support requests?
P.S
I thought I might as well add some information about User Interfaces and some design philosophies that could help the group tackle UI issues
User Interface Design: http://en.wikipedia.org/wiki/User_interface_design (Rudimentary Interface Design)
User Centric Design: http://en.wikipedia.org/wiki/User-centered_design (The group would probably be best suited for the UCD approach. Modules receive similar UI designs.)
User Experience Design: http://en.wikipedia.org/wiki/User_experience_design (Most advanced and requires the UIs of a website's menu system and its individual modules integrate with each other for better website navigation. Individual Drupal powered websites have unique needs so a UXD approach wouldn't work for the group.)

Comments
This is where the 'active usability projects' wiki page is for
Hi Stevejb. We created http://groups.drupal.org/node/7074 to keep a list of current UI priorities.
- Admin and site manager menus
- Node forms
- Views 2
Are the current 3 priorities indeed. http://groups.drupal.org/node/7074 should probably be reworked a little and link to 3 new wiki pages that collect all posts and issues on these subjects. The sticky 'active usability projects' page should stay a short page of lists. Feel free to start these wiki 'sub pages' for this!
People who want to add here should just subscribe to the group. Support requests belong in the issue queue, we really don't want to mix those in here :) If you find issues that are of interest, add a link to it in the relevant wiki. The usability folks have an informal meeting in IRC in #drupal-themes every monday: http://groups.drupal.org/node/7958
Thanks for clarifying that
Thanks for clarifying that yoroy.
I edited the wiki page (and made sure the teaser was unaffected) to link to the support forums and an issue tracker (its more convenient to track issues by visiting the group and then the issue pages.)
Priorities have been added along with a link to the most active and dedicated forum thread for that issue. If multiple groups are handling the issue we could have:
Issue Title (Usability Group Link)(Auxiliary Group Link)
Which seems to be the case for
Node Forms (Usability Thread Link)(GHOP Thread Link)
Views 2 (Usability Thread Link)(Design and Information Architecture Thread Link)