I admit to feeling some apprehension about calling myself an "atheist." There's something quite definitive about the term. I know there's a difference between strong and weak atheism, but still I find the label itself a bit confining.
I prefer the term "nontheist" in private, but in public I simply say I'm not religious. This has been helpful.
As for some other terms:
Spiritual Atheist? Now that's a term so totally open to personal interpretation. I could see where many Buddhists could fall into that category, many New Agers, Quakers, etc. I wouldn't use that term to define myself, but not for the "a-word." I have a problem with spirituality in the sense that it is often filled with the same fuzzy-minded theories I find so problematic (Law of Attraction, spirit guides, divine intervention, etc.). Then again, I can see how spirituality could also be more like a personal philosophy, the ability to recognize patterns within your life.
Secular Humanists? I certainly like their viewpoints and ethics. I feel the same way about Freethinkers.
I would certainly describe myself as a secular humanist/atheist, but when in a 'belief' discussion I simply say I'm an atheist.
cp