The ones I find most useful are the Z and Tab pie menus, since they bring up all the options instead of just toggling between two. So switching between solid and wireframe is slightly slower, but switching from solid to textured is much faster. The trick is to flick your mouse in the direction of the one you want to select, instead of actually clicking the button (that would definitely be slower!). It’s all personal preference though, and the default keymap is going to change with 2.8 anyway, so I wouldn’t worry about it much if you find it unhelpful.
