Mine is easy for me since i'm a Bellatrix fan so here are my top bella lines.

[Bellatrix]Neville long bottom's is it how's mum and dad
[Neville]Better now they are about to be revenged
[Luscious]Now lets everyone calm down shall we..Al we want is that prophecy
[Harry]Why did Voldemort wanted me to get this
[Bellatrix]He dare speaks his name you felthy half-blood

further down I like the screen after Sirus death

[Bellatrix]I killed Sirious black haha you gonna get me!!
[Harry]Crucio
[Voldemort]You have to mean it harry She killed him she deserves to die

Now for the half-blood prince quotes

[Bellatrix]Hello anyone home!! (sets Hagrids house on fire)

Those are my favorite of all time