I guess I'm mostly in the same boat with Chris. I was quite attached to my T pretty early on, and I still feel attached to him, in the sense that I care about him, I enjoy our communication, and there's mutual respect--much like I would feel for a good friend. I never feared for a moment that he would terminate me, nor did I particularly feel any worry or dread about when therapy would end (and even though it ended somewhat unpredictably due to his ill health, and I was sad, it wasn't soul-destroying.)

I guess all of this is evidence of healthy attachment. I'm not sure really how one knows if their own form of attachment is healthy or not, nor how one can predict attachment issues based upon childhood relationships. My FOO was, I suppose, "good enough" in certain ways that promote healthy attachment, but it was also quite an abusive environment. But it was only at the most highly emotionally charged moments that I projected my childhood expectations onto my T: generally, I could recognize him as a distinct person, who was probably unlikely to be or act like my parents.

So I don't think attachment style is entirely ruled by past experiences; we can, to some extent, choose to have different expectations some of the time.