Lately I've been reading rumours that the 6th edition Black Templars and Chaos Daemons codexes are going to be White Dwarf codexes rather than physical books. I certainly hope that this isn't going to be the case.
It has the problem that once the issue has gone out of circulation then new players can't get a hold of the codex, and potentially be stuck with an out of date codex since GW don't seem interested in putting the WD codexes up online as PDF's like they used to.
I'm going to keep an ear out on this and hope that it isn't true.