Terran i like second best. Like Protoss who have shields Terran have their cloaked units.

The Marine can shoot air and land units. Marines were normally rebels or criminals who have taken Neural Resocialization which makes them obey you.

Weapon:CMC-300/400 Powered Combat Suit, 8mm C-14 "impaler" Guass Rifle

Firebats are like marines but they shoot flames instead. They can only hit land units. Firebats and Marines both have a stim pack that increases their agression and reflexes but it has some side affects.

Weapon:CMC-660 Heavy Combat Suit Plasma-Based Perdition Flame Throwers

Ghosts have incredible psionic potential. The Ghost can perform a lockdown so you're enemy doesn't run away from you. Aswell as Cloak himself/herself so he/she becomes invisible and the ghost can also perform a nuclear strike which u build on a add on at the Command Center.

Weapon: Hostile Enviroment Suit, 25mm C-10 Canister Rifle, Personal cloaking Device

The vulture can lay spider mines but they only have three and then they can't lay anymore. These hovering vultures move very fast so they can harrass your enemy and make their escape, but if you do lose them its no worry cause tehy are virtually useless after u lay all of their mines.

Weapon: Anti-personel Fragmentation Grenades, Spider Mines

Goliaths work very effectively in a big group, they can hit air units and land units aswell.

Weapon:Twin 30mm Autocannons, Hellfire Anti-Air Missiles

The Seige tank can switch to seige mode when u upgrade it and that works great for attacks and deffense. The only bad things about a seige tank is when its in seige modeleftit can't hit anything next to it, when u're men are close to the enemy the seige tank blows them up too and their very slow, but gin up, this tank's range is the farthest of all the units.