to me the persistence of these sorts of words - sacred, spiritual, soul etc - actually indicates that they express something much broader and deeper than the ideas of the religious structures within which they have traditionally been promoted. I think they articulate something of the human experience that it is difficult to convey otherwise. That is why in an arguable post-religious secular society they still have relevance. There doesn't even need to be a hint of the supernatural for these terms to convey meaning.
As it happens I have been working on a bit of heritage interpretation for a nearby beach owned by the national trust. Identifying the aspects of the site that make it important to people is key to making any historical or natural stories about the place relevant. This particular site is characterised not by one specific attribute, but because people go there to spend quality time. That is a tough one to articulate in a useful way. Here is what came up with this as the theme (name of site left out) to underpin how the content and stories are presented.
"------- is sanctified by the countless hours people have spent there, in the company of nature and of loved ones"
This is entirely in the absence of any religious component whatsoever, but as I reflected on how to articulate the ineffable significance we had identified it was absolutely the best option... or at least the best I could do.