I'm using Firefox 8.0 and am enjoying the Group your tabs feature:
But I'm not always good at keeping it organized. I'm trying to find a way to automatically put certain domains in certain groups. Probably through a plug-in? All the tab related plug-ins just help cluster your tabs together and don't actually work with the "Group your tabs" feature (which is why I posted the picture, to avoid ambiguity, since grouping tabs can refer to a lot of things).