LEOs,MEOs, and GEOs, oh my!

While there are a large number of different satellite orbits, the most commonly used ones for man-made satellites are the LEO, MEO and GEO.
The LEO is a satellite that orbits around the earth in relatively close proximity to the earth. The definition of a LEO states that any area between 160 KM and 200 KM above sea level is a LEO orbit, for example, the international space station operates at an area that changes from 319.6 KM to 346.9 KM above sea level. A LEO satellite moves at roughly 27,400 KM/hr, or 8 KM/s, which is ridiculously fast. In fact, it’s so fast that the LEO may become impassable due to a cause-and-effect known as the "Kessler Syndrome", which states that space-born objects that are orbiting the earth will slowly build up.
Eventually there will be such a build-up of space debris that it will become nigh impossible to pass it without your ship becoming Swiss cheese. Due to the fact that’s there almost nothing to slow down an object in space, (It’s been theorized that theres a few hydrogen and helium atoms per square inch in space) the Earth’s gravity will keep the material in orbit for a few thousand years. Until it naturally slows down by coming in contact with the thin atmosphere up at 300 KM and goes into a "graveyard orbit", the debris will remain up in space. It’s been theorized that it will take a few thousand years for any debris to slow down that much.
A LEO is generally used for communications that require near-instantaneous communication, such as Internet games. Since they’re too close to the earth to broadcast over large areas, there has to be networks of them set up, therefore allowing them to bounce a signal from one satellite to the next until it reaches its destination.
A MEO is an orbit that is located above a LEO (2000 KM) and below a GEO (35786 KM), and are used for GPS tracking and other navigational instruments. An orbital period of one will usually last about 2-12 hours. One of the most well known MEO’s would be Telstar, which was a forerunner in MEO experimental satellites.
Finally, theres the GEOs, which operate at 42,164 km and stay in synch with the Earths rotation almost perfectly. (Each revolution takes about 23.9421 hours) GEOs are normally used for communication purposes, however, since they’re so far away from the Earth, the power requirements go up. Not only that, but there is a noticeable delay in communications, as much as half a second of lag can occur when a GEO satellite is used for real-time communications.