I like towers too... But I will admit that with some recent upgrades the bookshelf & sub system in my office, with all it's imperfections, is now sometimes the most attention grabbing system in the house. I don't feel any sense of loss of dynamics, but it's also a smaller room and doesn't get called upon to play as loud usually.
I would think the results you get will depend on the particular bookshelves, the other equipment and a whole lot on the room and set up. Like the others have said though, bookshelves on stands aren't usually really all that much less of footprint in the room - maybe a little less visually though.