My question is this: I see that I can either purchase Targus USB 3.0 Dual Video Adapter to split the monitors OR the more expensive dock Targus USB 3.0 SuperSpeed Dual Video Docking Station (ACP70USZ). I am looking at setting up two external monitors as a desktop configuration. I haven't purchased my laptop yet, but plan on purchasing a Toshiba Satellite 17.3' today. This can also be accessed from the hardware and audio section of the control panel. You may also have to change the audio settings to use your monitor's speakers.
Keep in mind that older laptops will not be able to have the same resolution as newer ones and that there may be a discrepancy between your laptop's resolution and the resolution of your monitor. That way, your screen will only appear on the external monitor.
Using a large monitor will change the resolution of the image on the screen.