I'm not going to write any long transcripes, because that takes too much time and you can find that in other GreenLeo sites, but below you can find some of my favorite GreenLeo quotes.
Computer Smashing Scene...
Greenlee: I'm all alone now, Leo.
Leo: You're not alone, Greenlee.
Leo: I'll be here for you. I'll always be here for you.

At the Beach in July 2001...
I let you go a bunch of weeks ago. At least I thought I had. I mean, I knew I didn't. Come on, I just acted as if I did and went through the motions. It didn't work. I make decisions and wonder what you would think about them. I go to a movie and wonder what you would think about it. I eat dinner and think about all those times we had dinner together and how much fun it always was and damnit, Leo, I go to bed at night and I see you when I close my eyes. I feel you in my heart. It's not over. You're not over. Not for me.

-Greenlee to Leo

Leo, if there's a chance that we can be something great, how can I walk away without giving it one last shot? How can I walk away from the best love I've ever know? Damnit, Leo. How can you?

-Greens to Leo

Greenlee: Haven't I? What did you feel? Really, Leo, tell me the absolute truth. What's left to lose?
Leo: I felt like I was home.
Greenlee: What do you feel with Laura?
Leo: Lost.

Greenlee and Leo decide to get married...

Greenlee: You're incredible. I am so happy. I have never been to happy in my entire life!
Leo: I want you to be happy.
Greens: I want us to be happy.
Leo: We are, we are.
Greens: And we always will be, I swear. We're engaged!
Leo: We're going to get married!
Greens: Oh! I love you so much!
Leo: I love you. I love you more than anything.

GreenLeo on roof before engagement party...

Greenlee: Why are we on the roof?
Leo: Because I want to spend a moment alone with you before we get caught up in the madness.
Greens: That's sweet.
Leo: See that sky, Greens? It's not big enough to hold all the love that I feel for you. I know I can't buy you a lot of expensive gifts and things right now, but I can give you all the love in the world. I want to be a man you can be proud of.
Greens: Leo.
Leo: Tomorrow we're getting that prenup signed. And after that I can't wait to make you my life.
Greens: I can't wait either! I love you Leo! You've made me so happy!

Greenlee says "i love you" to Leo...
Leo: Greenlee, you're going to survive. You're going to survive. I won't let anything happen to you.
Greenlee: Oh, God, you never do. You always come to my rescue, and this time its the worst. I am so sorry I got you involved in this. If anything happend to you, Leo, I would die. I love you.

Miscellaneous Quote:
I wanna learn how to use that toboggan that you gave me. I wanna get stranded on a desert island all alone with you all over again. I wanna be the father of your children, Greenlee. I wanna build around you. I wanna fall asleep in your arms every night. I wanna make all of your dreams come true. Please, baby give me a chance.

-Leo to Greenlee