I come from a similar direction. I wouldn't describe myself as a militant agnostic, but I am agnostic, at least insofar as most people understand the term. I've more recently begun to refer to myself as non-religious.

The problem I see with atheism (as most interpret the term), is that it is a belief that not only discards literal theologies such as Christianity, but also subtle ones that somehow associate our existence with something greater than the material, such as the possibility that we are living in a reality constructed by another form of life. I don't think this is a likely possibility. However, I have decided that there are probably a large number of possibilities that I haven't considered, or cannot comprehend, which would not jive with an atheistic stand.

When we look at history, we see people that could not begin to anticipate or understand things that we now experience. Our technological history is very young. On a cosmological timescale, it has not even yet begun. I believe a likely reason why our universe is apparently quiet in the EM spectrum with regard to other intelligent life, is because the reality that we currently experience is just an early stepping stone on a path that we cannot yet comprehend.

The reason why I consider myself to be an agnostic (or non-religious, as I prefer), rather an atheist, is because I seriously doubt our ability to fully perceive and understand the matter at hand. I do believe that science demonstrates truth and that every religion that I have encountered has it wrong; but I think we are too much a product of our present time and our present experience to make definitive statements on the nature of things. IMHO I think the best scientific approach takes a cautious view, and when it comes to the nature of existence, IMO the most reasonable ground is to say that the atheistic view is probably correct, and we can most reasonably act as if it were; however, we lack the information that we need to definitively close the book on the question. It is similar to my beliefs on anthropomorphic global warming: we are almost certainly warming the Earth, and we should act accordingly. However, there is a very small chance that we are wrong about this.

So, I suppose the problem I have with atheism is just the certitude that most ascribe to the definition of it. If the term was understood in a softer way, I'd probably be fine using it.