Anything by Douglas Adams, really, though this is probably my favorite:
Quote Originally Posted by Douglas Adams
Life... is like a grapefruit. It's orange and squishy, and has a few pips in it, and some folks have half a one for breakfast.
Also, there are so many awesome lines in both The Talisman and It that I don't want to do an injustice to by misquoting. But they're there, and they're fantastic.

This is definitely one of my favorite quotes:
Quote Originally Posted by Charles de Lint
There's stories and then there's stories. The ones with any worth change your life forever, perhaps only in a small way, but once you've heard them, they are forever a part of you. You nurture them and pass them on, and the giving only makes you feel better. The others are just words on a page.

Neil Gaiman has written some really, really great stuff, as well, and there are far too many good lines in Sandman to think about picking through. But there's one, probably from my favorite issue, that I already have copied down, so here we go:
Quote Originally Posted by Neil Gaiman
At the end of the procession, a bit behind everyone else, there were these two girls. One of them kept hesitating. She'd walk a few steps and stop. Like she's forgotten what she was doing, where she was. The she'd walk a little more. The other one...The one at the end. I think I fell in love with her, a little bit. Isn't that dumb? But it was like I knew her. Like she was my oldest, dearest friend. The kind of person you can tell anything to, no matter how bad, and they'll still love you, because they know you. I wanted to go with her. I wanted her to notice me. And then she stopped walking. Under the moon, she stopped. And she looked at us. She looked at me. Maybe she was trying to tell me something; I don't know. She probably didn't even know I was there. But I'll always love her. All my life.
The first line in his novel Anansi Boys is also great, I think.
Quote Originally Posted by Neil Gaiman
It begins, as most things begin, with a song.