For me, I'd have to say:
Minsc -
"Feel the backhand of Justice!!"
"Jump on my sword while you can, evil. I won't be as gentle!!"
(incomplete) "Keldorn, you have the courage of a thousand heroes!"
"All will fall to wrath of Minsc and Boo! All will fall!! All will fal-RAAAGH!!!"
Keldorn -
"And you, Minsc, have the strength of a thousand knights!"
(incomplete, ToB)"Tell me then, do you require the service of an old paladin?"
(to Yoshimo, incomplete) "Be careful what you may say, Yoshimo. The gods may turn you into a pumpkin, or some such."
Korgan -
"Aye, the dwarf will bloody do it!"
"Aerie, Aerie!! I swear by me grand-da's coal cart that ye were one o' them fey elves!"
Yoshimo -
"Ah yes, the city, with all its people and their accumulated wealth, yes?"
"Hiiiii - ya!! Heh, the tourists love that stuff."
Edwin -
"Edwin do this, Edwin do that. Somebody get this jerk a banana!"
Jan -
"You sound like Golodon."
"(burps) Pardon. Turnip reflex."
(his tales about all his uncles and such)
"You know, this reminds of that time, waaaaay back..."
"You know, we make an excellent team, like Drizzt and Wulfgar. Elminster and Volo!" (forgot the rest)
If anybody cares to add some, or correct the incomplete phrases, please do so at your convenience.