On the second part we'll use these objects to put together an abstract - futuristic city. A particle system on a plane is the easiest way to make it all work. Some compositing will make the final render look even better. The second part is on the video below.
Feel free to check the result on the video below. There are two vesions. One is the videotutorial result and the other is the tweaked result. I've only changed a few things; the particle number is set to 350 and the size is set down to 0.02. The camera was re-positioned for the animation to work without the camera passing through the buildings. Check both the results:
You can download both the result and the tweaked file from Blendswap.