I was disappointed to find out that Unrelenting Force doesn't do any direct damage. Also, I can't seem to find any information on how much damage shouts do.
Marked for Death does 3/sec for 60 seconds and -75 Armor as far as I know. Fire Breath does 90 Damage, the Ice thing does 2/sec so 120 in 60 Seconds FREEZE, meaning if you only autohit that target while frozen this should be the most damaging. The other ice spell does 90 dot damage, and slows wich can be really nice for multible targets...
Storm Call has the highest damage value over its duration, that or Call Odhaving . The base damage for Unrelenting Force is actually something like 10 points, although it does non-listed damage based upon physics. Odhaving could theaoreticly match it by doing the "lift and drop" attack to also inflict physics damage. Note that Storm Call has no IFF and cannot work indoors, greatly limiting its use.
Soul Tear is very strong with 300 damage and fills Soul Gem if it kills and reanimates the person it killed to fight for you for 60 sec. Only downside is this shout only hits one person unlike other shouts that can do AoE where you are facing. Completing the Dragonborn DLC you can add the Ice form effect to the Freeze Shout which has a much better cool down allowing you to do DoT from the shout and free range to attack without consequences. You'll only need lvl 1 shout to freeze most enemies.
favorite freakin shout lol i was waiting for someone to say soul tear. also cyclone does just about as much as fire breath and it has a couple of physics bonuses as it lifts and throws enemies. Cyclone with all three words is like storm call (but weaker) and unrelenting force (but stronger) combined.