Here are some choice bites for ubiquitous language.

“They have been at a great feast of languages and stolen the scraps” – William Shakespear

and

“Thought is the blossom; language the bud; action the fruit behind it” — Ralph Waldo Emerson

And on the need for simplicity, I really liked this one.

“There is never any justification for things being complex when they could be simple” – Edward de Bono

Robert Bravery commented on an old blog post of mine and I re-discovered this one

“Don’t indulge in any unnecessary, sophisticated moves.  You’ll get clobbered if you do” – Bruce Lee

Lastly, and the one I’m definitely going to use to stress the importance of working directly with the domain expert.

“Never hold discussions with the monkey when the organ grinder is in the room” – Winston Churchill

What a diverse group of people but such collective value.  Do you have any classic quotes?  Obscure quotes?