Returned mine today, at the Houston Galleria store. Applecare had me run through some diagnostic tests before I took it in, but nothing worked.
My battery was dead and the latch wouldn't work all the time either, so this PB was definitely not worth keeping.
After a bit of a hassle at the Apple Store, they agreed to give me my refund. I offered to show the guys behind the closed door the problem up close, because they said they couldn't see it, but the guy dealing with me said no.
I also noticed the floor PB I was reviewing (which had the line issue, btw) was very quickly returned to normal from the pages I had open (all the forum and appleplace sites open in windows on the powerbook, lol).
They sure closed those windows in a hurry.
So, first trek back to the supposed good side got me two weeks of fun with an OS that works, but a screen that sucks, and now it's back to my old a$$ Dell Inspiron 8000 for the time being, since I just sold my Vaio desktop as well.
At lease I get to order my new gaming rig tonight. Don't know what I'm going to do on the Apple side of things - very depressing.