It depends, are you willing to pay a slight bit extra for 3D world studio, 3D world studio has the more features, 3DWorld studio is basically Cartography Shop 5, but with a differant name and extra features, they work the same and were made by the same people.
And as Klu said, they are both level builders, so houses can be made, as for guns and cars, they would look extremely crude, for cars, guns etc I would try a normal 3D modelling program, there are plenty of freebies out there you can try
K I changed my name into a famous Samurai, but meh! Seppuku got boring after a while
