I think it's really important that you posted about this, not least of all so you can see what this series of thoughts represents for you now.
But one thing I can tell you is that you shouldn't see it as a setback of any kind. Progress in recovery isn't linear; it's not a simple matter of either we are feeling things improving (progress) or we're stuck or suffering a setback. Many times progress calls us back to something we thought we had all packed up and put back safely into the box. For whatever reason we just need to "go there".
I am just dusting myself off from what "felt" like a big setback on Sunday, but it was just something I needed to look at again. I got triggered, which I know will happen from time to time still, and suddenly there I was looking at crap from San Francisco in 1969. But I didn't go into meltdown, which would have been my response 3 years ago. That already showed me one big difference. And I could see everything wasn't unraveling on me either. What I did see was that I had never really allowed myself to grieve for a terrible loss I suffered back then, and that sometime I would have to revisit this. But I could do it on my own terms now - my life wasn't going to be hijacked. Another big difference.
I see the same thing in your post. My guess is that 3 years ago the thoughts behind this post would have hammered you really hard. That didn't happen here in 2008. Not even with the dark thought that "Bobby is dead" (which for guys from our generation likely means "Bobby doesn't matter"). As you say, it doesn't discourage you.
Nobody living can ever stop me
As I go walking my freedom highway.
Nobody living can make me turn back:
This land was made for you and me. (Woody Guthrie)