On Wanting to Say "God Bless You"

"God bless you always."

It's a phrase I hear almost every day here in the highly-religious community of Santiago Atitlán, Guatemala- from my fiancee, from her family, from friends, from neighbors and people on the street.  It's a darn good way to express a genuine concern for another's well-being. 

I wish I could say it, too.  But, given my lack of religious faith, I'm afraid I can't.

This little problem represents a lot of what's missing in a secular, non-religious world- a world where, as Nietzsche put it, "God is dead."  Without belief in a divine being, how does one express the sentiment behind "God bless you?"  "Have a nice day," doesn't cut it. 

I might just be looking for an adequate phrase- or maybe this superficial concern covers a deeper longing for much, much more.