There are a lot of different ways to use 3D. The following are a few ways you might want to use your Blender skills.
It might seem odd, but if you watch animated shows such as Futurama and American Dad, in outdoor scenes or ones with cars, planes, and rockets moving in them, you can tell that they were originally created in 3D and were then colored to match the rest of the 2D animation. One director told me that his 2D animated show is all done in 3D but shot with a camera setting that flattens it out again. He finds it's faster to make it that way than with Flash or other 2D animation packages.
This is the market Blender was originally built for, back in the days when it was the in-house system at a Dutch advertising firm called NeoGeo. Blender is a good tool for local TV stations and advertisers because it can do a lot quickly and deliver quality results at a price that even the smallest TV station's manager will appreciate. Networks such as Azteca America have used Blender in some of their studios. Blender is good for schools and universities as well as personal video projects.
Blender has started to be used for feature films such as Plumiferos in Argentina and The Naughty 5 from India. In addition, short films such as Sintel show that Blender has the capacity to do it. Hollywood has been known to use Blender for pre-visualizing a movie before it's made, to figure out how the movie will look when they make it. Pixar uses Blender for its intern program.
This is a hot new trend in films. You need to have two cameras render the same scene from slightly different locations, just as if your eyes are slightly apart. However, the cameras have to work in sync with each other. Think of how your eyes shift if they were to go from threading a needle to looking at mountains in the distance. Blender can do this as well as any other 3D animation package.
Blender is good for rendering complete animations or for making graphics to be used in Flash, gifs, or HTML 5 animations.
Blender has its own Game Engine. Therefore, it's good for making your own games and showing what you can do. You can also export Blender files for use as assets with other game engines such as Ogre, Unity, and CrystalSpace. You can find out more at sites such as www.blenderartists.org.
The Blender Game Engine and Blender's physics packages make it possible to make your own flight and driving simulators.
Nowadays, we are seeing digital signs almost everywhere, from HD monitors in McDonalds to the building-sized signs in Las Vegas. With user-selectable resolution, you can make animations in Blender to whatever size you need, for whatever use. The files can then be uploaded to the Web and distributed to displays all over. This is a quickly growing market for advertising companies.
Because the Python language allows using a scientific data set, anything from weather to a rocket to medical simulations can be animated. NASA uses Blender at some of its locations as does the National Radio Astronomy Observatory.
With animation for the legal system, the models are often simple though realistically proportioned. The clients are paying for accuracy, not fancy graphics. Blender's physics engine can help you make realistic animations. You can make car crashes, track bullets, and help when a crime comes to trial. It's an in-demand way to use your animation talents.
Clients of a multi-million dollar project want to see what they are getting before they spend their money. This is a very specialized use of Blender and other 3D animation systems. You can give your clients either a high resolution video walkthrough or use the game engine to make it interactive.
Blender can output a virtual reality .X3D file to create virtual reality on the Web that can be used interactively on most browsers.
A set that you see behind the TV personality may not exist at all; it might be a set modeled and rendered in Blender.
The Blender game engine can be used to make interactive illustrations or lessons, or Blender can provide graphics for Flash or websites.
For anything from dinosaurs to the moons of Saturn, 3D is probably the best way to demonstrate what can't be seen directly. This can be used to show others the ideas in your head and the visions you see, taking them to places that are too small, too large, or too dangerous to visit in reality.
If you do good work and can demonstrate it, many employers don't care what software you use. I know of one animator who perfected his Blender skills while serving in Iraq. He took what he did to the big studios and soon he was working on major Hollywood films. Get involved in animation social media groups. Check out other animators' portfolios.