In general my experience has been the floor standers can certainly bring more authority to the music, more often than not bringing the bass down lower and, of course, moving more air in the room. Where I feel that monitors excel is in creating the width and breadth of soundstage, as well as in their disappearing act and imaging. Don't get me wrong, floorstanders can do all that too, and pretty darn well. But I'd say, at a given pricepoint, the monitor will excel those specific areas, especially the later two (again, as a broad generalization). I'd have to agree with Larryi that monitors do not necessarily lend much authority to a convincing full-on orchestral piece. But they do render the more simple acoustic and vocal pieces in very satisfying ways! It just depends upon what you are after, and what programming you listen to most of the time.
Marco
Marco