My preference is to kill 'em on sight. Not that I DO that mind you. It's against the law:)
I live in the middle of town and I kill them on sight also. Get one of those silenced air rifles. It is most effective on cats.
I have trapped cats in the past. A person had about ten to fifteen of them. A lot of the trapped cats went to the pound. Eventually the offender stopped letting them roam.
I have never shot a cat either.