Going out onto the strip and pile driving one thousand zombies. 
 
You feel fucking refreshed after shit like that.

One line.
 
I saw what you did there

the time i killed that zombie was pretty great

" the time i killed that zombie was pretty great "

" One line.
 
I saw what you did there "

Chuck's one-liners after killing psychopaths were pretty great, as was Slappy sitting up after you kill him. 

Carl the pathologically punctual postman. I just wish I could of unlocked a Postman outfit; postmen have never been so awesome!

" One line.
 
I saw what you did there "

My favorite moment was coming back to the bosses that had given me so much trouble before (Antoine, I'm looking at you) as a level 50 and beating them in a matter of minutes. Playing that game as a lower level and as a higher level is like night and day. I was shocked at how much easier it was to beat the psychopaths when I was at levels 40+. I knew it would be easier, but not that easy...
 

My favorite moment was finding out the bosses make the game not fun for me.  I seriously went and got a list of all the missions containing psycho bosses so I could avoid them.  I will do them when I am at least level 25-30.  Other than that my favorite moment was making the rocket launcher for the first time, when screwing around trying to make random combos.  Super Gangsta.

" My favorite moment was coming back to the bosses that had given me so much trouble before (Antoine, I'm looking at you) as a level 50 and beating them in a matter of minutes. Playing that game as a lower level and as a higher level is like night and day. I was shocked at how much easier it was to beat the psychopaths when I was at levels 40+. I knew it would be easier, but not that easy...
 

SPOILER WARNING: Click here to reveal hidden content.

Of course, there is also TK and Sullivan, who I never want to fight again, no matter what level I am..

"

Buying the keys to the sports car and drifting into crowds of zombies is really up there. 

" @Everyones_A_Critic said:

" My favorite moment was coming back to the bosses that had given me so much trouble before (Antoine, I'm looking at you) as a level 50 and beating them in a matter of minutes. Playing that game as a lower level and as a higher level is like night and day. I was shocked at how much easier it was to beat the psychopaths when I was at levels 40+. I knew it would be easier, but not that easy...
 

SPOILER WARNING: Click here to reveal hidden content.

Of course, there is also TK and Sullivan, who I never want to fight again, no matter what level I am..

"

SPOILER WARNING: Click here to reveal hidden content.

Sullivan sucked, yeah. I see what they were trying to do; giving you a climatic fist fight like the one in DR1 against Brock, but considering barely any of your attacks would register on him it was just yet another matter of exploiting how the battle is not meant to be played.

"

I agree that using the car to barrel through an exponentially high number of zombies is good clean fun.

anything i have ever done with the blambow or boomstick or a combo weapon that uses a lawn mower

Killing zombies by hitting them in the head with a whisky bottle. I don't know why, but it always make me laugh.