I have a few dirty rats (rodent type) hanging around the outside of my house. Want them gone. What is the most effective method for getting rid of them?

Went on the Bunnings website and they have everything from baits, Nooski's (lacky band thing), electronic sound emmitters...all the way to the good old fashioned wooden trap like the one featured below.

P.S. I hate cats so I am not getting one of those to solve my problem.