Unrelenting Force, Dragon Aspect, Aura Whisper, Whirlwind Sprint, Cyclone, Slow Time, and Become Ethereal are the ones I use the most. Both forms of Call Dragon (Dawnguard required for the second) are good as well. Dragonrend is handy against dragons, obviously
Slow time definitely, and iam also talking in meta sense. Its one of the most subtlest shout while in application could be arguable the most versalite. Hell its probably the first shout that i want to have if iam a dragonborn irl. For all kind of power and thuum dovahkiin has, the slow time shout is the one that push his power tier in the scale of demi-god or higher end of high fantasy character. And l can't imagine how the lore version of the slow time shout would be if the game version is such OP. Maybe it could completely almost like stopping time (because its really that slow).
Put The dragonborn in any fantasy setting with just slow time shout, he would probably congquer all most of it. Bonus point add all his arsenal and magic, but not the other dragon shouts
i agree
its caled a power like beast blood or shadow stone
Frost breath + dragonborn frost = ice form on steroids
Soul Tear(from Dawnguard DLC) is handy if the enemy is at low health, but really not for anything else. Slow Time is also useful, but really only when you have all the words. The one that I recommend is Ice Form. It takes a while to recharge, but it clears down armies of enemies and getting your bearings down and thinking what you should do next.
My favorites are:
Dragonrend , because I get tired to waste my arrows on a flying target,
Dragon aspect , because it's a good armor addition and a cool looking effect,
Whirlwind sprint , because you can move quickly (could have been more useful in game).