As is so often the case, the definition and the practice of atheism are two entirely different things. The word atheism, as you noted, means "without god." In practice, Atheism is the rejection of god. As you also noted, how can you object to something that does not exist? Perhaps our definitions of religion differ, but Atheism (with a capital A) is most definitely a belief system that shares rampant contradiction with most religions.
In practice, I see agnosticism as living without god, a life where the existence or nonexistence of god bears no importance.
I completely agree with Matt with the importance of making a positive difference in the world, and letting your actions speak rather than using the cloak of organized religion to show who you are.
Jill, there is certainly a contradiction in agnostic pantheism, but the part of agnosticism that resonates with me is accepting doubt and being comfortable with not knowing all of life's answers.
Please note that I said my beliefs "run toward" pantheism. I did not say I am a Pantheist. My life and my beliefs do not fit into any "ism" or any capitalized school of thought.
It is human nature to seek easy answers. I reject that. I don't need answers to be happy with or unafraid of life and death. I would be so bored if the answers to life's great mysteries were spelled out clearly. Give me answers and I'll give you new questions. (And almost all of them will be asked at least partially in jest.)
.