I don't know whether you'd count them as Christian fiction, but they are at least fiction with Christians in: The Sparrow and A Canticle For Leibowitz.

Thanks for the recommendations, I'll certainly have to give those a try. The latter sounds extremely interesting.

One note I should have made earlier: while "Christian SF" doesn't seem to really exist as a genre, there is plenty of religion in SF, ("Dune" and "Enders Game" spring to mind). Heck, Asimov assumed a Christian audience a lot of the time.

That latter comes with a slightly cynical attitude towards the Church, although not towards Christianity itself

An interesting point, and I'll have to read the book to see what you mean in context. However, this was one of the large points in "The Visitation" that started off this whole conversation. You have two characters both "burned" by the Church, but one who takes this out on God and the other who recognizes that Christianity is not to blame for the people who have hurt him.

if, as I'm rather ashamed to admit I sometimes do, you draw a line between "sci-fi" and "proper novels", they're definitely on the "proper novel" side.)

In my own mind I lump the best sci-fi (or what I've deemed the best) in with "proper novels". However, most of the "thrillers" that come out these days wouldn't be considered by me to be "proper novels" either, so I draw this imaginary line a little bit differently, I suppose.