Jim,
I was gonna mention Hook and forgot as I was going down the cover of Design Patterns. I ought to write Hook in the margin. You are exactly right each one doesn't live in a vacuum from the others. It's kind of Patterns++. And some of them overlap so that adds to the nebulous boundaries.
>And don't forget the almighty Hook pattern as well as the mediator, in fact how about a factory that creates hooks to decorate a mediator. It may sound like I am trying to be funny, but in fact I am trying to point out that patterns do not have to exist alone, using them in proper sets can be a very powerfull way to solve some very complex problems.