I'm an atheist, too, and I subscribe every single word of your post.
We are metaphoric monks in a metaphoric monastery, so if I agree to be called "friar" now, I should not object to be called "angel" or "spirit" when I'll be dead. Indeed I don't object to it, and certainly I'll not do then.
My materialistic point of view is that I don't know if (and I don't believe that) there is an immortal part of what is me, but I do know that each one of us can achieve a little bit of immortality doing something useful for the others. And useful can be a very wide word.
So, I can't think of anything more appropriate than remember who is no more here by mean of what he did. I'm thinking of a place (a crypt? is it the right word?) to remember them and their work. I'd love to be there when my time comes.
Rule One: "Do not act incautiously when confronting a little bald wrinkly smiling man."