The Terran army of StarCraft II will never be complete without infantry. They are the front line, they are the support, they are the primary raiders and spellcasters, and they are your bread and butter units. Knowing their strengths and weaknesses are essential to your success in the beta, and at release in July. Not even Raynor can save you in the campaign if you don't know that a Reaper can jump over cliffs!

Once Medivacs and your opponent's counter units come into play, you have to be a lot more careful with your Marines. You cannot just stand still and fire when all of the area of effect weapons are on the battlefield. Micromanagement comes into play more than ever once the Colossi storm the battlefield, or the High Templar storm it quite literally. Marines are quite nimble when under the effects of Stimpack, and need to be moved away from these chaotic abilities before they are charred to a crisp.

That's just the tip of the iceberg. The hard numbers and more are available here!