But I'll go against other commenters here who are saying that blender is an amazing piece of software. For a long time I was really passionate about CG, and even worked as a 3D artist in a few stuidos, and guys, if you want to start learning 3D - do not start with blender.
If you want to get into modelling - check out Nevercenter Silo, it is the most convenient 3D modelling tool you'll ever use, it is amazing.
If you want to understand the basics of all the CG, and learn how professional VFX are done - learn Maya, it is used for everytning, and is the absolutely best way to get started with 3D, once you understand it - you can do whatever you want and easily switch to any other app if you wish. It is the industry standard, and the best way to learn the foundations.
If you want to see how the perfect CG software looks like - check out sidefx Houdini. It will blow your mind, it is like linux/emacs/lisp of CG world. It is elegant and brilliant and perfect in every way(except that you can't really model in it, that's why you need Silo).
Also take a look at Zbrush, it is a sculpting software, looks alien but is really brilliantly done. You can look at the gallery here - http://pixologic.com/zbrush/gallery/, it's amazing. If you have a tablet and some solid drawing skills - you can start creating amazing things in it really quickly.
If you want to try compositing - use Nuke from The Foundry.
All these packages have free trial versions. Silo is cheap, Hoidini has an apprentice version that you can use for free, indefinitely, with no limitations except for output resolution(and maybe a small watermark, I don't remember).
Compared to these packages - blender is a horrible mess. It is worse than what gimp is compared to photoshop. Just like gimp, theoretically you can use it, and even make some good things with it, but you really, really don't want to.
Maybe it's a gem of open source software, and I respect that. But if you are getting into computer graphics and want to learn and understand how it works - hell no, use something else.