Withnail:
I must say… [points fork at Marwood]
That that, represents a degree of hypocrisy in you, that I had hitherto suspected but never detected, due to highly evasive skills.
Network:
We’re mad as hell, and we’re not going to take it anymore!
Vito Corleone
“I made him an offer he couldn’t refuse.”
Said without undue emotion, and not in a prideful, boastful manner. Just a simple, clear, statement of fact.
This may be disqualified under the “inspirational” restriction, but I think:
Here’s looking at you, kid.
is right up there on the “Greatest Movie Quotes” list.
Others, from the same obscure film:
**I’m shocked, shocked to find that gambling is going on in here!
Of all the gin joints in all the towns in all the world, she walks into mine.
Louis, I think this is the beginning of a beautiful friendship.
Ilsa, I’m no good at being noble, but it doesn’t take much to see that the problems of three little people don’t amount to a hill of beans in this crazy world.
Round up the usual suspects.**
“You wanna know how I did it? This is how I did it, Anton. I never saved anything for the swim back.”—Vincent Freeman in “Gattaca”
Please.
The greatest movie quote of all time, bar none, end of discussion is:
“If you wanna shoot, shoot. Don’t talk.”
One that always gives me chills:
The Usual Suspects
“It was Kayzer Soze, agent Kujan, the devil himself! How do you shoot the devil in the back? What if you miss?”
and one that always makes me teary.
The Iron Giant
“Superman!”
I’ve come here to chew bubblegum and kick ass, and I’m all out of bubblegum.
They Live
“Tyrone, you know how much I love watching you work. But I’ve got my country’s five hundredth anniversary to plan, my wedding to arrange, my wife to murder, and Guilder to frame for it. I’m swamped.”
Prince Humperdinck, The Princess Bride
As for ‘inspirational,’ I’d have to go with a quote from Kill Bill Volume 2:
I’m coming Pai Mei.
But as just plain Great quotes, one that comes to mind is:
I don’t mean to sound queer or nothin, but I think unicorns Kick Ass!
The quote that shaped my early life into what I am today:
D.C.: Lloyd, why do you have to be like this?
Lloyd Dobler: 'Cause I’m a guy. I have pride.
Corey: You’re not a guy.
Lloyd Dobler: I am.
Corey: No. The world is full of guys. Be a man.
And so I’ve tried to be ever since. I’m not always successful, but there’s a lot of truth (and heart) in the trying.
Wish me luck. 
It’s also the most perfect last line:
“Nobody’s perfect”
“You’re gonna need a bigger boat.”
Paul Newman in Slap Shot: “You know, your son looks a …”
“Baby, you’re so money – and you don’t even know it!”
Heh.
Since my favorite lines from Gattaca and Field of Dreams have already been mentioned, I’ll go with the ending monologue from American Beauty
In The Color Purple when Miss Celie finally got the courage to leave Mister and he’s trying to make her feel like a failure. I love the part when she is replying and says,
“Everything you done to me, already done to you”
tears me up just typing it out now.
KHAN!!!
A recent one would be the KillBill… " don’t take the members though… I own them now". Very funny.
Otherwise I really like Gandalf’s quotes from LOTR. Some who deserve to die and other not… who are you to take their life from them quote.