You see, Super+S just does what it says, it's a workspace switcher. That is, it shows you an overview of the workspaces. BUT -not- an overview of your open windows/apps. For example it doesn't show you the minimized windows. So you need solution 2 and 5 if you want a full overview and management of ALL your open windows, in my opinion
@tertian: In that case, you need to make it explicit in Solution #2 that you mean to include minimised windows. Perhaps if a new option is provided to choose whether or not to include minimised windows in Expo (Super+S), that will solve Solution #2.
Using 'Scale Addons' in the compiz-fusion-plugins-extra pack of features I can zoom in on windows in spread mode by right clicking on them (and then right click again to go back to the overview) and I have set a keyboard shortcut to close what ever window my pointer is hovering over. It works really well for some fast windows management.
There are also options to label the windows with their application title, and some other things. However, it only shows windows in current workspace, this does need to be changed.