JK's Favourite Room, and Room of Requirement

[mtwelovett]

No: HPFGUIDX 70637

Josephine wrote:
I remember reading somewhere that JKR, when asked which room at 
Hogwarts she'd want to spend an hour in, said that it was one Harry
had already been in, without knowing its secret/importance. 
<snip> it came to mind again during OoP, what with the DA meetings in
the secret room. I'm wondering, could this be the room JK spoke of? I
think it seems unlikely, as Harry has never been in it before, plus it
changes depending on what you need.

Lauri replied:
 Excellent question, Josephine!  The quote from Quick Quotes is:

 "Go straight into a certain room, mentioned in book four which has
certain magical properties Harry hasn't discovered yet! "
 
I also suspected it was the Room of Requirement but wonder when Harry
may have been there in book four?  Perhaps she meant the Prefects
Bathroom instead? It sounded marvelous to me! :)
 
 Lauri

Now Me (mtwelovett):

What if the Room of Requirement was the room in which Harry found the
Mirror of Erised in SS? Then he would have been in it before without
knowing it's secret/importance, but was also mentioned in book 4 by
Dumbledore at the Yule Ball as the room with the Chamber pots.
Although I really like Lauri's idea of the Prefect's Bathroom
especially if it has more secrets and importance. 

I keep wondering too if the Room of Requirement changes locations as
well as "what's inside." (kind of like the staircases at Hogwarts,
which we haven't heard much about since SS, was this just a fun detail
or will it be significant later?) Dobby showed Harry where Dobby knew
the room to be, but what's to say it is always on the 7th floor? Maybe
this is something to look for on the Maurader's Map... or does the
room even show up if you're outside of it. Would be something
interesting for Harry to study... in trying to find a new Home for DA
to continue since Malfoy and others know more or less the location
they were using for the secret meetings... although it would be realy
funny for Draco to go back and try to find it and discover it as a
broom closet or something.

Mtwelovett