The Hydrox: the only cookie that sounded like some sort of bleach was involved. I know people who absolutely swore by Hydroxes, claiming them superior to Oreos in every way, but I never understood that. They were always dry and dull, I thought. In fact, they were less sweet than Oreos, which came along in 1912 - four years after the introduction of the 'Drox.
This division paved the way for later debates about Star Trek vs. Star Wars, and Mac vs. PC. Wars were fought over less.
Hydrox and Jell-o? No.