Todd Rhoades (who calls himself a Christ-follower) has an interesting list of ten theological issues that he feels the church will still be facing for at least another decade. Soteriology (the doctrine of salvation) heads the list, but I'm not sure that the list is in any particular order. Homosexuality is there, of course; what sort of churches we'll be looking at in the future is there; social justice - and Christian consumerism. It's a good list, though no doubt others could add to it.
The comments make interesting reading. A couple of people think the list is pretty ho-hum, because it covers ground that the church has been looking at for some time, but others make some worthwhile points, including the man who defends Open Theism.