In Mumble very well implemented feature Overlay. I'd love to see this feature in TS3.
Code:Overlay The overlay is a feature that will overlay the nicknames of users in the channel or users talking over your currently running game. That means you will be able to see who's listening and talking ingame. Mumble provides overlay support for Games using Direct3D 9/10 or OpenGL on Windows and OpenGL using games on Linux/OSX.