I wrote a longer version of this post, but it has been eaten by a grue. This one is different.
I was about to start writing the first version of this when I noticed that Dana asks "What kind of atheist are you?". An interesting coincidence, because in some way this post is related.
I must admit a certain amount of confusion with the term "positive atheism". I don't see atheism as inherently positive or negative. (I see the step of throwing off irrational faith in favour of reality as a positive one, but that's a benefit of becoming an atheist, not of being one in the sense that it's not an active process.)
Being an atheist, living as an atheist, is neither positive nor negative. You can live a positive life, or a negative one, or anything in between, and be an atheist. Atheism is orthogonal to positivity.
This might seem incongruous, given I just had a post in the 21st Humanist Symposium. Humanism is the sort of philosphy people tend to associate with "positive atheism" and the Humanist Symposium's brief is definitely about living positively, but humanism and atheism are quite different - many atheists are humanists, and many others are not. Many humanists are also not atheists. But, nevertheless, many atheists are attracted to humanism. I agree with many of its tenets, but I don't see humanism as connected to atheism, so to me it's not really "positive atheism", it's just humanism, and neither is necessary to the other. Similarly, my post was about using probability to figure out that some apparently worrisome things may be nothing to worry about, and that an understanding of probability could help lift burdens of worry from our lives. But again, it's not atheism that's doing that. Atheism's job came earlier, in removing the attempt to explain such events as the acts of an incomrehensible and all-powerful god (the positive step of becoming an atheist). With that non-answer out of the way, there is room for the rational explanations of probability to make their positive contribution. So it is with humanism and other positive worldviews that many atheists have.
I'm generally a very positive and content person. I happen to be positive, and I happen to be an atheist.
But the phrase "positive atheism" (and for that matter, all the negative epithets theists throw at atheism) just doesn't have any more resonance for me than "yellow music" does.