It'd be nice to be able to symbolize (Bold, Italic, etc) Group Layers in the TOC. That way it would be easier to know which items in the TOC are groups when all layers are collapsed.
This is really an excellent idea. Would assist greatly with navigating complex map documents. Suggested from a client at a training course this morning (Esri Australia), and I thought I would look and see if someone had come up with this idea already - and suprise suprise, someone had!! Would be a great enhancement.