Google Sketchup

For those who haven't found out about this program should try it out. It's a simple to use program with great results and minimum effort. It's great for designing buildings, cars or whatever you wish to create (even humans or animals can be done). It may not have the same real-time rendering as other programs but that can be solved by importing the file into another program then rendering it. Watch the tutorials and enjoy the program!

 This is the official site where you can watch tutorials and download the program. http://sketchup.google.com/

And here is a little sample of what you can do with this program.