Blender 3D: Noob to Pro/Sequencer
What is the sequencer? 
When I first began using blender, I assumed it was basically a 3D modeling and animation program, but what I didn't know is that it also included a fairly powerful non-linear video editor. With the sequencer you can take your rendered animations and splice them together, chop them apart, add pretty effects, and do all sorts of fun things that most people would go perform in a completely different application... But we're using Blender, so forget about those other programs.
Why use the sequencer? 
The sequencer adds a lot of flexibility to your rendering process, using the sequencer you can basically render the same animation as many times as you'd like from different camera angles, and then load the animations back into the Sequence editor and cut 'n' splice them as you desire. You can achieve some nice effects such as blurring that would probably be less efficient if performed during rendering, also an important feature is the ability to add sound clips to your animations. The sequencer also allows you to layer multiple Blender Scenes, which can lead to some very interesting results.