This is my current Terran build for team-based play, and it is generally what is expected amongst other Terrans unless you scout otherwise. Instead of using gas to get mauraders, stimpack, concussive shells, and medivacs for MMM bio you spend the gas on tanks and the excess minerals on marines.
For this build, you will have two barracks with no attachments in the early game. You get a refinery after your first barracks and build a factory after you get 100 gas. Then build tech labs for both factories, research siege mode upgrade and start tank production. Once you have extra gas you can start building reactors on your barracks to build marines twice as fast. Tanks are very gas heavy, so your excess minerals will be used on marines. The combination of tanks in siege mode and marines surrounding them make it difficult for melee or air to attack this army since the marines will handle anything air or up close while the tanks destroy any ground forces within range. I think the siege tank is the best ground unit for terran. You can defend from almost any ground attack with well placed siege tanks and cover your team mates. The siege tank falls short on mobility considering how in order for siege tanks to be effective they must be in siege mode and cant move. That's where your team comes in and helps with the mobility with blink stalkers or mutalisks to help get to a position quickly where your tanks cant get to in time.