There are probably dozens of awesome lines uttered by my characters that I just can't recall, but off the top of my head are the following, one for each of my PCs.
1) Cedric, immune to Death Spells for a little while, wanted to absorb as many as possible in a Death Elemental fight so everyone else couldn't be deathed. To that effect, I decided to be bold. I taunted the line of death elementals, rapidly absorbed three or four death spells and bellowed "Death?! You think you can kill me with death spells?! Do you know who I am? I'm Cedric ******* Fruvous, you can't Death me!!"
(As an aside, this plan worked for about one or two waves. All the NPC's were coming from a gate and playing the same monsters over and over again, rather than different monsters. It did lead to a great line from Henry the Mad also who pointed me out to another NPC and said "That's Cedric ******* Fruvous, you can't Death him. Stab him instead.")
2) Rex the Dog Scavenger: "Everyone sucks but us." Then I slammed the door in Emilio's face
3) Find'rth: "Please don't swear around the women in my group, our culture finds that very distasteful"
Kyril: "I understand, no offense intended. Now I've got to go take a crap that would choke a dragon."