Heaven Canceller (many times):
"Just who do you think I am?"
Accelerator (against Touma, Awaki, and in the video game at the beginning of a fight)
"sanshita"
Misaka Sister:
"...MISAKA leaks the information at the appropriate time"
Touma:
"...Then I'll just have to drag her out of hell!"
Tsuchimikado, to Aleister:
"...but stand before him with a single illusion, and he'll destroy it (something like that)"
Stiyl:
"gtfo, n00b! (...) **trips over a stone**"
and finally...
Biribiri:
"
Watashi ga tobaseru no ha...
coin dake janai!!!
Kore ga watashi no
zenryoku.. GWAAAAAAAH!!!!
"
It's not just coins I can shoot!
This is my
real strength!! **then follows what I call Hyperailgun**
This epicness... same level as Accel-pwned Awaki...
EDIT: damn, forgot that
Index I ep18
Railgun ep2