you should still manage your wires, even if you dont have a window. i dont have a window, i dont really like them, but at times i wish i had one...not really that important to me. i know there's a beast in there heh heh...and my wiring is clean as a whistle.
see:
http://i69.photobucket.com/albums/i57/toranagasama/slitwo.jpg
manage your wires.
for one thing, it helps your air flow.
for another thing, you wouldn't want to open your case and be like, "geez, that is some messy stuff".
am i right?