My name's Ben so usually I just go with BEN

Either SIA (first three letters of my name) or ASS.

Either my initials WJM or WIZ (for wizard)

Had I been old to actually have visited arcades, it would have beenNNO or profanity.

FKU

PRO

GCH 
 
My initials. 

BUM, USA or LUV

WIL 
 
Every time, for all time, I have the WIL to succeed. 
 
Also it's my name.

either my initials, RAB...
or if I'm being lazy/dumb AAA

JAK

OPP!

AAA, ASS, and PIB.

Shortened version of my name

Sometimes I use my initials.  Sometimes I just go with MOM.

JBE, my initials.

ESS

ASS

CAH my initials.

DAN, since my name is Daniel

ROK.

MOP, or my initials, GEM.

Mine was ADE, due to my name being Adrian.  It had the advantage of being really quick to enter too, which was handy on machines which gave a punishing time limit to put in a name.  I swear, on some machines it was more difficult to enter a high score than it was to play the basic game at times.  I could also never understand why many games on home consoles kept the time limit on entering a name too.  I mean, not like it had to kick a player off quickly so more money could be taken on the machine.

My initials, KPK.

My middle name LEE.

RAM, my initials.

usually ZID

Mine was always JER, which is the first three letters of my name instead of my initials. I have no idea why I decided to go with my first three letters instead of initials, just did.

" RAM, my initials. "

TAK, My initials

" @Vager said:

" RAM, my initials. "

*suspicious squint* You're not Richard Mitchell, are you? "

ASS, always and forever.  When I'm feeling peppy I go with FUK.

MAR   basically my first middle and last name initials.

ACD

" MAR   basically my first middle and last name initials. "

ALI.

AOR

" RAZ  or something dumb like OMG or AAA "

Mine was easy TED over at http://www.starbasearcade.com/locations.php

ASS, because I was always a child when I played arcade games, haven't played one that wants your high-score name in forever.  I would probably just use my initials, MLP, now.

G B F

I had the simple job of using my nickname, LEE.

Hmm, maybe all those years of typing my name in capital letters in Cruisin' USA is what inflated my ego.

RNG (my initials)

AAA (who doesn't?)

FUK (hahahaha)

UNT

DEV or AAA

if my score is shitty is AAA

if i am proud of my score it's EDR