Unless there are serious balance changes in the future a number of SC2 Commentators (Huk, Day9) have suggested that this will become the standard Terran play. Usually 1 techlab and 2 reactors, these addons can quickly be switched, allowing the deployment of Banshees (once air superiority has been obtained) and Hellions, or swapping to Marauders to break a Siege tank grouping. The power from this build comes in its flexibility. In a losing battle, the Vikings can always land and wait for Marine support (as Vikings are an air to air unit). One of the important points of this strategy is to use Vikings to establish air dominance. The basic idea here is to build a Marine, Tank, Viking force, using the Vikings to give Line of Sight to the Siege tanks (which can fire further than they can see) and using Marines to fight off Air harass. The synergy that units from these buildings provide have cause this build to become increasingly popular outside of TvT play. The name derives from having one of each unit producing structure: 1 Barracks, 1 Factory, 1 Starport. The 1:1:1 was first popularized by the player The Little One (TLO) and has become the standard in TvT play. A key point to remember is that the initial Barracks can be used for scouting or to produce Marines (which help an early Mech army). Top Zerg players (such as Artosis and IdrA) have said that Terran Mech is so powerful it is 'Broken' (a term to mean unbalanced) against Zerg. Additionally, heavy Siege tank forces are effective vs Hydra/Roach armies. This is especially effective vs Zerg players going Muta/Ling as upgraded Hellions are powerful vs Zerglings and Thors do splash damage to Mutalisk. This usually involved building one Barracks before going to 2 Factory and pumping out hellions for early harass and then transitioning into a more stable Thor/Siege tank force.

Terran Mech grew out of early hellion harass. You can also transition into Bio mech, or add Ghosts on for TvP. Additionally, Medivac's provide for drops which increases the mobility of your army. Medivacs are key to Stim based play, as any force that stims is necessarily at reduced HP for the remainder of the game. The build continues to evolve into the late game by adding on a Factory and Starport for Medivac support. The timing push here usually comes at about 40 food with a heavy Marauder/Marine force with Stim. A Terran economy can readily support 3 Barracks. Openings usually consist of 3 Barracks (sometimes called Rax), 2 with techlabs and 1 with a reactor. Terran bio revolves around building a Marine/Marauder/Medivac force for a nice timing push. Obviously there is a lot of variation and overlap between these builds but I'm going to try and lay out the broad strokes here. The three major builds in Terran play are:

As a result I'm going to try and lay out a couple of the broad strokes, but unlike Protoss or Zerg these are not going to be succinct build orders. There are literally dozens of Terran builds and possibly hundreds of Cheeses.

Starcraft 2 terran build order