There have been some instances where I found that shouts like "Disarm" and "Dismay" have been useful. Whenever I stumble on a gang of enemies that either I triggered, or the game scripts to have them all come at me at once, have been some of those situations.
Spoiler For instance, most of the Dragur around the tomb of Olaf One-Eye in Dead Men's Respite have had their weapons knocked out of their hands because of their static low(er) level. This was great for my non-armor wearing mage who can't take a proper beating and still live to tell about it. Dismay has also saved my mage's hide when a few (again, lower level) NPC's come a runnin' at me.
I love "Storm Call". I can go up to an exterior wall of a fort, use the two or three-worded version of the shout, then count to about 20. All of the effected NPC's (or most of them), are lying dead on the ground. But like others have said, your followers are also targets. This shout is indiscriminate on who gets effected by it's lightning bolts. Since I spend 90% of my time going solo, this doesn't effect my gameplay whatsoever.
The most useless shout... or should I say, the most of my least used shouts... is "Animal Allegiance". More often than not, the creatures that end up fighting for me has their effects worn off before the fight is over, and they end up turning on me.