All writers get rejected, but some go on to such amazing fame it's hard to believe they ever were. At 50 Iconic Writers Who Were Repeatedly Rejected you'll find a list of authors with links to just how bad it got. Good dose of reality and a lesson in never giving up.
(And yes, I've been rejected tons too!)
Thanks to Nathan Bransford for the link.
Update: Don't click on the Dr. Seuss link as it goes to a bogus site. The others appear legitimate, however, and I've emailed the webmaster.