I'm atheist rather than agnostic, but the way I feel about it is...
What my sense of "me" is is, in essence, a big neural net a network of neurons that is shaped by what happens to me and that reacts in largely predictable ways (always taking chaos etc. into account). For people I know well, I carry my own little "models" of them around with me bits of my own neural net that are given over to an idea of the person. It's that that allows me to think "Oh, mum will laugh if I tell her that" or "DH would love this book" or "So-and-so would say something very scathing about this movie".
So what each of these people is is a big neural net, and what I have for each of them is a vastly-cut-down model of their neural net. The better I know someone the more of my own processing power is devoted to them and the more accurate my model of them will be.
When someone dies their net is gone forever, but my model of them cut-down and over-simplified though it may be remains. To me it's as if part of them carries on, and whenever I think "So-and-so would have laughed at this" it's as if they are, in some sense, laughing at it -- or at least the part of them that carries on in me is laughing. And everyone else who knew them well will also have their own mental models of that person. So while the person as a unique individual is gone, potentially dozens of imperfect simulations of them are going about the world. And parts of them will live on even past me in the way they've influenced my way of thinking, which will influence the way in which I bring up my children, which will influence the way they think... and so forth.
You will never see her as an individual again, but part of her is always with you.
Anyway, that was a bit rambling, but it's how I think about it. I did think it was all my own idea, but I read a book by Dougklas Hofstadter last year and he has the same view (although he expresses it much better than I do) so perhaps it's a common way of looking at the world.