What are the various veteran organizations and associations out there?

Recently I asked a question about the pros and cons of joining the VFW and the American Legion. This brought up some other organizations, some I've heard of and others I have not.

Vietnam Veterans of America, the Marine Corps League, Disabled American Veterans, the National Guard Association of the United States, and a bunch of others. Some were even unit affiliated like the 82nd Airborne Division Association.

What groups have you joined and what spurred you into doing so? Have they had a positive impact on you or your community? In recent years have these groups challenged the good old boys club notion that younger vets seem to have?

I signed up for another six, so I'm not getting out anything soon. I have begun to wonder though, when it is time for me to leave are organizations like this worth putting time into. It's been easy to see that not everyone understands military culture, and there are stories you don't tell to people who just won't understand the context or meaning. So I can understand a desire to meet up with people who will understand that.

I can also understand the desire to continue serving outside of the uniform, doing something constructive that supports fellow veterans and your community.

That said I've seen more than a few people share their negative experiences with these kinds of organizations.