I find the big sets like that have lots of large pieces specifically designed to make the building and are not much use for other things. Personally I would buy a large tub of lego bricks and then some different cars/ helicopters etc.
You can buy tubs such as this which contain different size bricks and a few wheels, windows, doors and a couple of people so then you can build whatever you want. Don't be fooled by the size of the box though, it is only about a third full! We bought a small box like this and then bought a load second hand off ebay to top it up with.