Here are all the ones I remember reading:
The Iliad
The Odyssey
Beowulf
Canterbury Tales (Chaucer)
Brave New World (Huxley)
Tale of Two Cities (Dickens)
Julius Caesar (Shakespeare)
Romeo & Juliet (Shakespeare)
Yellow Wallpaper (Gilman)
Things Fall Apart (Achebe)
...and tons of Greek/Roman mythology (ie, Medea)
EDIT: as I'm reading through the other posts, I realize how many I forgot. Red Badge of Courage,
Hatchett (which I recommend - we read it in 5th grade and it still stays with me), The Lottery, To Kill a Mockingbird.... and I know I'm still missing a bunch.