Terran v Terran: One Barracks Fast Expand

This build utilizes a fast expansion to capitalize on an early economy to transition into mech or bio depending on your personal preference.

10 – Supply depot (at wall)
12 – Barracks (at wall)
13 - Send SCV scout
15 – Orbital command upgrade
15 – Marine
16 – Supply depot (at wall)
17 – Marine
18 – Command center

After the second Marine is finished, float your Barracks back into your main base and construct two additional Marines

19 - Refinery x2
21 - Bunker (at wall, where barracks was)
25 - Factory
27 - Orbital command upgrade
28 - Tech lab on barracks (for factory)
30 - Supply depot
31 - Starport
31 - Reactor on barracks (for starport)
6:20 - Scan opponent's main

From here you can  react to what your scans and scouts see at your opponent's base.

Fast Expand, No Gas: Banshees and Cloak

Gas First: Engineering Bay at 5:30, Turret in minerals and production area

Cloaked Banshee: Viking, save for scans

Marine / Tank timing attack: Tank / Viking

Terran v Terran: Marine Hellion Elevator

This aggressive one base build uses a medivac to forgo your opponent's forward bunkers and walled off ramp attacking with marines and hellions.

10 – Supply depot
12 – Barracks
13 – Refinery
17 – Orbital command upgrade
17 – Supply depot
18 – Factory
19 – Reactor on barracks

Constant Marine and Hellion production

21 – Starport
25 – Medivac

At this point you have about 3 hellions and 8 marines to attack with, the key is to use the medivac to lift your units up into your opponent's main base, you can continue pressure and continue rallying units and lifting them into your opponent's base. Hopefully your opponent sustains sufficient economic damage from the attack, after the attack is done you should expand and go for a marine, tank, medivac composition. It is also a possibility to add a tech lab to your starport and produce cloaked banshees to kill damaged SCVs in your opponent's mineral line.