I have quite a number of shouts already: frost breath, fire breath, the one that calms creatures, the one that clear the skies, the Flash one and the one that reduces armor. But I find myself constantly using only the good old fus ro dah.
Even though it has a fairly long cool down (45 seconds after using the three words) it is a very good crowd control and I usually only have to use it once during a hairy fight to give me time to heal/buff myself.
What other shouts do you think is useful and in what situations?
combat wise as a mage I only use three shouts, ethereal, freezing, and force;
ethereal for fights/situations where is hard or impossible to kite and damage is dangerous, this is very rare tho, force when Im fightting frost resiting mobs/bosses that cant be freezed/dont last very long, and freeze is my main shout, since it allows me reprieve when my mana is too low to cast paralysis or simply when I want a large group of mobs setup for my, limited use, of master rank aoe casted spells.
edot: oh forgot to say slow time I used alot vs other casters and archers, because it allows me to avoid missing spells alot, aswell as dodge their spells/arrows aswell.
as a warrior I use alot of different shouts tho, well not having almost all keybinds filled with tons of different spells help, but I use force vs bosses/hard liutenants, yol, for dmg and dmg multiplier, wuld for escaping or quickly closing the gap, the dark brotherhood one on armored dudes (I love swords too much to go for axes or maces) and I think thats about it.
Slow Time.
To be quite honest, I find the shouts Overpowered so I try to use them the least I can

The only time I break the rules is when I meet a particulary annoying frost mage.
THOSE BASTARDS JUST MAKES MY BLOOD BOIL! RAWRG!
I use wuld there