Page Manager (and family... i.e. Panels) is starting to get some more traction within our community. New users are finding it, using it, and asking awesome questions about it every day. I've done my part both from a development side as well as a teaching front to try to help that along as much as I can, and I'm very pleased with the fact that the community is beginning to find these tools and really appreciate what they can do. With that being said, I want to pedal some of my own page_manager based wares on those of you who might listen.
Contextual Administration 7.x-1.x RC3 is imminent. For those of you who have not used context_admin or don't know what it is, context_admin is a module that utilizes the power and flexibility of page_manager to locate administrative interfaces at arbitrary urls. For example, if you have a news article view as /news/view (default tab) then context_admin gives you the ability to add a "Create New News Articles" link at /news/add... or an administrative VBO at /news/admin etc etc. Since these are all page_manager driven pages you have the luxury of specifying who has access to these pages in a much more granular way than the typical 'permissions' system.
There are many great features stuffed into context_admin, including examples of how to prefill node references (ala nodereference_url module, but with a lot more options) and menu auto-population, and taxonomy tree building and much much more. As I said, RC3 is imminent and I just have some access plugins to test at this point.
In addition to all of this, the newest dev of context_admin has a wrapper that exposes all of its administrative plugins to panels to be used within the panels interface. This is a totally experimental feature, but I've been pretty happy with the results thus far. I hope this post helps bring some more converts to the system. Please feel free to track me down in irc or in the issue queue. I'm EclipseGc and spend lots of time in #drupal-contribute as well as other places.