I think it's cool, but I don't think straight edge and veganism necessarily go hand in hand. I think just because you indulge in certain things every now and then doesn't mean you don't respect your body.
I see veganism as not having control over other being's bodies. But I have control over mine and my body functions perfectly well despite the occasional bender. So I really don't think it's for me.
HOWEVER
My opinions have changed slightly since last time we had this discussion

I know that for some people, even a little of any certain substance is too much, either because their body can't handle it or because they might have a family history of addiction, which can make you more susceptible to it. I don't like the "purity" argument, because it suggests that the majority aren't "pure" and that is heading a little too far into religion for me to be comfortable with.
I still hate labels and I still hate the sense of superiority that some people have.