Initially, I just wanted some software that would allow me to do some simple two-dimentional animation, but my buddy found this "Blender" software and I thought, "What the hell..." Now, about three weeks into my studies (there are a LOT of tutorials and help files out there) I'm beginning to get a slight grip on the software's interface, though you should really see some of the truly amazing things people are doing with it. The software is free, but be warned, the better your system, the faster, your renderings will be. Some of these took me a few minutes to design, but much l o n g e r to render (animations in particular).
Simply put, the more complex your subject is, the more time it will take. LOTS of MEMORY and a FAST proscessor are really going to enhance your experience greatly. The user interface is BRILLIANT, yet really complicated to master, I assume, as I have yet to master it. This is what I initially wanted a computer for, back in like, 1990, when I got my 486 DX2 with 4 megs of ram and a 213 mb hard drive (only cost us $1,500.00)
Go to Blender.org if you're so inclined. Have fun!