After reading all these posts and the newsletter, my geuss is that the new track will have a similer background to what QWERTY went though (i.e, not being suited for the new album, but still a decent track) but I'm almost 100% sure they wouldn't put any new ablum tracks on a LPU CD anymore.
One thing people are forgetting is the newsletter said "studio album hits".
I'm pretty sure the HT demos will be ones we alredey have, but with a chance of a Papercut one as well.
The Meteora demos will be the gold in it all (presumeing the HT demos unrealsed), and will make a very intresting interview question after they stated they wiped them all. My geuss (not simply because I want to hear them): Breaking the Habit, Somewhere I Belong and Faint.
The Minutes to Midnight demos are easy, my geuss: Shadow of the Day, Leave Out all the Rest and maybe TLTGYA with mike's vocals.