While doing some research for the toolbar in Blender 2.5 I collected a bucketload of toolbars from various apps to determine what would be useful for Blender.
Along the top are various horizontal toolbars, while the vertical ones are beneath. The challenge is to have something that is clear, compact and fast. Traditional painting apps work well with icons, because the concepts map to real world items quite well. This isn't always the case in 3D though, because the tools are more abstract - there's not really such a thing as a real world extrude tool, at least not something that's be useful as an icon.
Although what we have in 2.5 is already quite nice, it's interesting to look at different ways of displaying tools in a GUI. It might be nice to eventually have horizontal tools too, for example.
Until then, this is some food for thought.
