Yup, they are the things that keep the door from swinging too far open. And they have a detent that can help hold the door open... right now any breeze at all will swing it shut. The service guy called it a door check strap, but since then I've looked for one online and they seem to be referred to simply as a "door check" by other places.
Only other thing I've needed, beyond routine maintenance, was some sort of airbag-control wiring harness in the steering column. It had to be replaced just 3 months ago.
Matt0420, be glad they are only slamming your doors, and not getting behind the wheel while slammed.

That does get irritating, I know.