It seems that a lot of TvT games become a contest on whoever can achieve air superiority (thus giving their siege tanks greater range over the enemy). It could be said that tanks are OP (tanks + 1 bunker > marine rush; tanks > proxy bunker; tanks > thors; etc.). However, I know of a build that can end the game quickly if done right.

"Thor Drop"
10 depot*
12 refinery
13 rax
15 orbital
rax done -> factory+tech lab, marine*
17ish depot*
factory done-> armory
@100 gas -> starport
@200 gas -> thor
medivac
siege tech
siege tanks/vikings

*keep building depots and marines with spare minerals

With this build, you fly a Thor behind the enemy mineral line and destroy their economy or kill them. If they don't have enough mech (Thors decimate marines/reapers), they'll lose a big chunk of their miners. This can lead to you taking the advantage (enabling map control) and ultimately winning.

Of course, if they destroy the Thor before it can do enough damage, you wasted a bit of minerals, but not "a lot." The factory and starport will still be used for pumping tanks and vikings later on.

Are there any other TvT build orders that are useful? (Reapers are getting nerfed, so I won't bother with reaper rush as often).

..You could rush Marauders. They're quite effective early on, but you have to plan on ending the game pretty fast.

Aren't Marauders a pretty good counter to this Thor drop? They take three hits from a Thor and they also deal bonus damage to armored, if he went a marauder heavy build it seems like he'd rape the thor and plow into your base before you get any standing army up

Sadly, the marine is the counter to the marauder. This was demonstrated when my friend decimated a marauder rush using mass marines.

It's tactic to tactic counter. In order to mass marines, you need to have a reactor, and an extra barrack. Terran isn't a reactive race, so if your opponent went tech, then he cannot quickly switch to mass marines. Stop talking useless 1:1 counters, because they mean nothing. Sure, if he switched to marines midway from a factory, then get marauders AND hellions. Cause you can.

Also, we know from fact that marines own marauders. But that's because you won't have enough marauders by the time he has enough marines to kill you. Just use your brains. Bunker up and put your marauders in it. It'll hold. Get a tank, upgrade siege. You have a chance once you do.

I am not a terran player, but it is true that a well placed ThorShip can seriously mess up anyone that is not prepared.