Attributed to ChinChilla, whoever that is :) 

In Harry Potter and the Sorcerer's Stone:

10. "No problems, were there?"
9. "Can you smell something?"
8. "Hermione, stay below and stop it going down."
7. "Fred said it hurt a lot, but I think he was joking."
6. "There's talent, oh yes, and a nice thirst to prove yourself."
5. "The big one/The one we've all been waiting for."
4. "Give us a look, Lee, go on."
3. "I see what McGonagall meant... you really are a natural."
2. "I didn't realise it had to be so wet."
1. "Now don't forget that nice wrist movement we've been practising!" 
	(Now we know what Prof. Flitwick gets up to in his spare time)

In Harry Potter & the Chamber of Secrets:

10. "Let's do it tonight."
9. "He looks like he wants you to grab hold..."
8. "Stupid... useless... thing." (Poor Ron.)
7. "So? I bet loads of people here can do it."
6. "A bit more. One good push..."
5. "...don't fulfil their requirements... half an inch, if that..."
4. "He's been looking dreadful for days. I've been telling him to get a
move on."
3. "Wood's been teaching us new moves."
2. "When you've finished eating, you can leave."
1. "How thick can you get?"

In Harry Potter & the Prisoner of Azkaban:
10. "Well, I hope he's up to it."
9. "Bang him on the counter."
8. "--for Humungous Bighead."
7. "Don't forget to wipe it after you've used it."
6. "Dear, dear, I'm getting too old for this..."
5. "He's coming, Molly!" (Fun with the Weasleys)
4. "You won't have to do all the work this time, Hermione. I'll help."
3. "Yer've got ter stroke 'em..." 
(Advice from Hagrid. Wonder if he's been taking lessons from Flitwick...?)
2. "He's made some changes in the line-up and seems to be going for
size rather than skill."
(To the Slytherins, size is everything)
1. "His head was so swollen." 
(Well, we already knew that Snape was jealous of James).

In "Harry Potter & the Goblet of Fire"
10. "If that was the best Rita could do, she's losing her touch."
9. "It's a bummer all right."
8. "It was four foot long before his parents would let me shrink it!"
7. "...with a horrible fang on it, really, Bill, what do they say at
the Bank." (Bill is really into body piercing)
6. "How many times, Kevin? You don't touch Daddy's wand."
5. "Dobby likes work, but he wants to wear clothes and he wants to be
paid, Harry Potter."
(Be afraid, be very afraid...)
4. "My own brother, Aberforth, was prosecuted for practicing inappropriate
charms on a goat."
3. "Well, if they're any bigger than this lot, even Hagrid won't be able
to handle them."
2. "Always the same, we can't resist showing off when we get together."
1. "Does he still think I entered myself?" (Ron has amazing faith in Harry)

A couple for the slashers from the fourth book:

1. Harry disentangled himself from Ron and got to his feet.
2. "What is this?" he cried, when he saw Krum on the ground, and
Harry and Dumbledore beside him. "What's going on?"

Disclaimer: All these lines come from the Harry Potter books,which are
by J K Rowling. If you review "Eww! That's disgusting!" I'll just know
that you have a dirty mind too :-)