Ninja Speed Box is a context sensitive tool box that changes when you are in different modes.
The modes are: No selection, single object, Multiple Objects, vertex, edge, and face.
The different modes contain functions mostly used in that mode.
When you only have faces selected it will change to face mode.
When you only have vertices selected it will change to vertex mode… etc.
you can also add your own buttons to each context shelf
http://www.creativecrash.com/maya/downloads/scripts-plugins/interface-display/c/ninja-speed-box