Theese are the reasons i think Spike is best for Buffy, please note theese are not in chronoligical order.
1)Spike was able to love Buffy without having his soul.
2)He refused to tell Glory who the key was even after being tortured.
3)She treated him like a man even though he knew he didn't deserve it. "I know i'm a monster, but you treat me like a man"
4)When Buffy's friends where all in hospital and Kendra was dead, Spike was the only one who helped her.
5) He was the first one to know Buffy had been in heaven not hell.
6) Even when he would have been easy to kill with the chip, Buffy didn't kill him.
7)When everyone kicked Buffy out, Spike was the only one who was there for her. "A hundred plus years, and there's only one thing I've ever been sure of: you. Hey, look at me. I'm not asking you for anything. When I say, "I love you," it's not because I want you or because I can't have you. It has nothing to do with me. I love what you are, what you do, how you try. I've seen your kindness and your strength. I've seen the best and the worst of you. And I understand with perfect clarity exactly what you are. You're a hell of a woman. You're the one, Buffy."
8)Buffy loved Spike before Chosen, Cassie couldn't of predicted Buffy telling him she loved him if she didn't already love him. "She'll tell you. Someday she'll tell you."
9)Buffy chose him over Angel to be her champion. "The amulet was supposed to be worn by a champion."
10)He saved Buffy from bursting into flames. "Life's not a song. Life isn't bliss, life is just this, it's living. You'll get along, the pain that you feel, you only can heal by living. You have to go on living. So one of us is living."
11)He died saving the world. "i gotta do this"
AND FINALLY
12) Spike got his soul back for Buffy.
Other memorable Spuffy quotes:
"Spike, I love you" "No you don't be thanks for saying it"
"What are you doing here, Spike? Five words or less!" "Out... for... a...walk...bitch!"
"Don't I get a cookie?" "No!"
"A Bear! You made a bear! Undo it! Undo it!"
"I'm getting the brush off for Captain Peroxide. It doesn't necessarily bring out the champion in me."
SPUFFY <3
1)Spike was able to love Buffy without having his soul.
2)He refused to tell Glory who the key was even after being tortured.
3)She treated him like a man even though he knew he didn't deserve it. "I know i'm a monster, but you treat me like a man"
4)When Buffy's friends where all in hospital and Kendra was dead, Spike was the only one who helped her.
5) He was the first one to know Buffy had been in heaven not hell.
6) Even when he would have been easy to kill with the chip, Buffy didn't kill him.
7)When everyone kicked Buffy out, Spike was the only one who was there for her. "A hundred plus years, and there's only one thing I've ever been sure of: you. Hey, look at me. I'm not asking you for anything. When I say, "I love you," it's not because I want you or because I can't have you. It has nothing to do with me. I love what you are, what you do, how you try. I've seen your kindness and your strength. I've seen the best and the worst of you. And I understand with perfect clarity exactly what you are. You're a hell of a woman. You're the one, Buffy."
8)Buffy loved Spike before Chosen, Cassie couldn't of predicted Buffy telling him she loved him if she didn't already love him. "She'll tell you. Someday she'll tell you."
9)Buffy chose him over Angel to be her champion. "The amulet was supposed to be worn by a champion."
10)He saved Buffy from bursting into flames. "Life's not a song. Life isn't bliss, life is just this, it's living. You'll get along, the pain that you feel, you only can heal by living. You have to go on living. So one of us is living."
11)He died saving the world. "i gotta do this"
AND FINALLY
12) Spike got his soul back for Buffy.
Other memorable Spuffy quotes:
"Spike, I love you" "No you don't be thanks for saying it"
"What are you doing here, Spike? Five words or less!" "Out... for... a...walk...bitch!"
"Don't I get a cookie?" "No!"
"A Bear! You made a bear! Undo it! Undo it!"
"I'm getting the brush off for Captain Peroxide. It doesn't necessarily bring out the champion in me."
SPUFFY <3