I remember there was a meeting in Florida some years back to discuss a symbol for Atheism and I was unable to attend. I was told the meeting ended with no agreement but soon afterwards the Dawkins Foundation began promoting the capitol @ version (or however you describe it). The main problem I see with this choice is that it is not, as far as I can tell, an electronically transmittable character In other words, it is not included in the Unicode standard (http://www.unicode.org/)
That is a real problem in the 21st century. All religious symbols are included in the Unicode standard. This has concerned me for quite some time and I finally got around to voicing it so I hope others will comment and we’ll see if there is any support for either selecting a new symbol or lobbying whoever to include the current symbol into the next version of Unicode (which now includes emojis so that would be nice).