Meaning of life

[Tahir Wood]

it was the milieu, not the theory in itself (with which probably 
only a tiny minority of them grappled extensively), that gave meaning 
to their lives.
Yoshie

This is obviously true, but that still doesn't settle it. I mean I have no problem admitting that the idea of communism adds meaning to my life. Why not? Hell rock and roll gives meaning to my life, so does my job even (sometimes I think so anyway) and women do too. What sorts of things legitimately give meaning to one's life outside of religion? I'm not religious so does that mean my life is must be "meaningless"? What is this thing?
Tahir