First, my own agent success story interview on QueryTracker:
6 Years/4 Manuscripts/200+ Queries

I am inspired by the following authors who, while faced with much rejection, worked hard and REFUSED to quit. I hope you will be inspired too.

Caroline Starr Rose

Plow to the End of the Row
 "An almost foolish optimism has kept me working, trusting that the next editor or the next agent or the next story would be the one to launch my career."

Working Hard and Believing
"Over the years, in the midst of rejection and doubt, in the isolation of the pre-blogging era, two things have kept me going, the ideas that I have something unique to say, and my work can only improve if I keep at it."

Meg Cabot
My First Sale by Meg Cabot
"I don't know why I didn't quit. Especially when I got such widely divergent rejection letters, everything from the word NO! scrawled across my own query letter...."

Laurie Halse Anderson

Triaging Rejection Pain
"The last stage of grief is Acceptance. Yep, your book was rejected. But you are alive. Your creativity has not diminished. You are capable of learning more and writing better. Rejection, in all of its forms, is part of being a writer...."

Shannon Hale

Rejection Letters on Her First Book
"...just because your book or you or anything you do is rejected by some, doesn't mean it's no good trash for everybody. Stick with it...."

Alex Haley
received a rejection letter once a week for four years as a budding writer. Later in his career, Alex was ready to give up on the book Roots and himself. After nine years on the project, he felt inadequate to the task and was ready to throw himself off a freighter in the middle of the Pacific Ocean. As he was standing at the back of the freighter, looking at the wake and preparing to jump into the ocean, he heard the voices of all his ancestors saying, "You go do what you got to do because they are all up there watching. Don't give up. You can do it. We're counting on you!" In the subsequent weeks, the final draft of Roots poured out of him.
~ Bud Gardner, "The Power of Perseverance", Chicken Soup for the Writer's Soul

And when you feel as if you just can't take another "no"....
Rejecting Rejection (The Writing Barn Blog)

By whom are you inspired?