I won't say much about the build order, I'll concentrate on how you should place your defense. -First get a few SCV's on minerals
-Build barracks and supply depots
-Pump out marines just for stopping rushes
-Try to expand early on, cause you'll need lots of resources
-Start building bunkers in your chokepoint in one straight line, but don't block yourself off, leave an empty space
-Fill the bunkers with marines (I don't like firebats, cause I think that it's better to stop the enemy,than letting it close in to damage your bunkers)
-Get SCV's on gas
-You should already have upgraded marine firing range
-Place a few turrets behind or in front of bunkers
-Build a factory
-Research siege mode and pump out tanks
-Get them behind your bunkers (a lot of them)
-Build a comsat station (to spot cloaked units)
-Now concentrate on wraiths, and research their cloaking ability
-Move them near your bunkers to defend against large flying units (i.e. carriers)
-For air defense, build triangles of turets with 2 goliaths in the middle (against drops)
This should be a great defense against any types of units, although I only recommend this it for experienced players, cause newbies would probably waste too much time on this and would forget about offense.

CreepColony's Opinion: If you're playing on a non-mucho money map like Lost Temple, you should place your first bunker near your command center.