You don't need 2 of the same monitors, unless you want it that way for aesthetic reasons... They can even be 2 different resolutions if you really didnt care. Also, it completely depends on what you're going to be doing on the "main" monitor as to what kind of graphics card you'll need... Just doing Microsoft Word/Excel? Web surfing? On board graphics are fine.... Gonna do anything that has to do with higher end video? Just read reviews on where video cards fall in respect to others in a video environment you'll be using and choose one that has 2 outputs. Thats really all there is to it.