Following are some different quotes I've collected:

 Inspirational Quotes:       

• "Life is change. Growth is optional. Choose wisely." Karen Kaiser Clark
• "Trust yourself. You know more than you think you do." Benjamin Spock, MD
•    "Great minds discuss ideas;
     Average minds discuss events;
     Small minds discuss people."   - From an annoying forwarded email.  (They aren't all junk.)
• "We cannot all do great things,
  but we can do small things with great love." Mother Therasa
• "It's always darkest before the dawn" - Not sure where this ones from...
• "Good judgement comes from experience, and experience comes from Bad judgement." Barry LePatner
• "Education is what you get when you read the fine print.
  Experience is what you get when you don't." Pete Seeger
• "A life spent making mistakes is not only more honorable, but more useful than a life spent doing nothing." George Bernard Shaw
• "After I'm dead I'd rather have people asking why I have no monument than why I have one." Cato The Elder

 Quotes of Caution:

• "Those who do not remember the past are condemned to repeat it." George Santayana
• "What you have become is the price you paid to get what you used to want." Mignon MCLaughlin
• "I have never seen a greater monster or miracle than myself." Montaigne
• "You can't shake the devil's hand and say your only kidding"  -'Your Racist Friend' by TMBG
• "The two hardest things to handle in life are failure and success." ANONYMOUS
• "I don't know the key to success, but I know the key to failure is trying to please everybody." Bill Cosby

 Light Hearted Quotes:

• "Growing old in Inevitable; Growing up is Optional." on a shirt from Aussie T company
• "Tis strange - but true; For truth is always strange; Stranger than fiction" - Lord Byron, Don Juan
• "The difference between genius and stupidity is that genius has its limits ." Albert Einstein
• "Age is not important unless your a cheese." Helen Hayes
• "Millions long for immortality who don't know what to do on a rainy afternoon." Susan Ertz
• "The time you enjoy wasting is not wasted time." Bertroud Russell

 Quotes from books:

• "To recognize you are the source of your own loneliness is not a cure for it. But it is a step toward seeing that it is not inevitable, and that such a choice is not irrevocable." - Robin Hobb, Golden Fool
• "Death is always less painful and easier than life! - And yet we do not, day to day, choose death. Because ultimately, death is not the opposite of life, but the opposite of choice. Death is what you get when there are no choices left to make." - Robin Hobb, Fool's Errand
• "That's what they should teach us here, he thought, turning over onto his side, how girls'
  brains work...it'd be more useful then Divination anyway..." - Harry Potter And the Odrer of the Phoenix
  
  From: "Accidents May Happen; Fifty Inventions Discovered by Mistake" by Charlotte Foltz Jones
• "Grown-ups never understand anything for themselves, and it is tiresome for children to be always and forever explaining things to them." - Antoine de Saint-Exupéry
• "All the world is a laboratory to the inquiring mind." - Martin H. Fischer
• "Discovery consists of seeing what everybody has seen and thinking what nobody has thought." - Albert Szent-Gyorgy
• "Mistakes are a fact of life. It is the response to error that counts." - Nikki Giovanni

 Quotes and religion:

• "Religious belief rests on a foundation of faith. Seeking empirical evidence for support of one's faith-based beliefs therefor could be considdered pointless. Or even blasphemous." - Column by Steve Mirsky in Scientific American, Feb 2005