i feel like it's obviously gallifrey, but that may be because the emotional impact of when gallifrey is mentioned is always much greater. there's the whole flashback sequence in tSoD, and of course that whole three part finale was about the doctor finding out that there was another survivor and what that meant. and there are the times it's brought up in s4, like FoP, when the doctor needs donna's help to set off the volcano because he can't kill so many people again, and then later when she's pleading with him to save someone, and he snaps he can't save anyone, because he couldn't save anyone on gallifrey. and of course he's wrong. plus all the stuff in tDD, wanting not to be the last, being afraid of it, having his new family taken away again so quickly; and all of the stuff about how hard it is to stop killing once you start. plus the line, "the man who dare not look back, out of shame" in JE.

um, yes. so that kind of stuff sticks in my mind more than, "not that you're replacing her". yes.