Response to "God Bless" when parting company
What should the correct response be (from someone not overtly religious) if someone says "God bless" when parting company?
"Bye now" or "Bye" doesn't seem an adequate response.
I think it comes down to A) how religious the other person is, B) how religious you are, and C) how much you want to avoid potentially insulting the person. If they are very religious and you are not, and you want to avoid any hint of insult to their religion or any potential conflict, better just say something religious or at least agreeing back:
"Thanks, same to you".
If you can't stand to say something that even acknowledges their beliefs, I think it at least doesn't hurt to acknowledge their sentiment, so you could just say "Thanks, bye." That's probably what I'd do.
I had a friend in college who liked to respond to "God bless" with "Goddess protect". As I recall he did so just to be different from us other geeks who would sometimes respond with "Live long and prosper".
Seriously, though, I think that a polite "Thank you" should be sufficient.
I'll often reply, "Take care." Sounds a little warmer than "bye," and not particularly religious.
You could respond with a Jewish farewell, illustrating that not everyone sees the world the same way, but also probably alienating your friend
Shalom!
Or you could be polite and simply say
you too!