I used to be FoamFighter, because I LARP. Changed it to something a little hipper.
Adam
Still and only. Wish I had the forthought to capitalize the “G”. 
Too lazy to change it.
McKenna before Our Winter of Missed Content, and then a long time when I was sort of commuting between NY and Boston with my computer in various states of disarray. I totally forgot McKenna’s existence and became the lovable alley cat I am today.
I am the Doper formerly known as particlewill
That is all.
From '99-00, I used to be Smug…
now I’m meek.
[sub]And it’s all your fault.[/sub]
I started as Khadaji.
Way back in the old days I used to be called ChiefWahoo. I don’t remember why I changed, except that people kept assuming I was a Cleveland Indians fan. Which isn’t that big of a deal. Oh well…
Same as it ever was, same as it ever was.
Used to use my RL name.
Then, changed it due to some unpleasant e-mails that I didn’t want following me home, so to speak.
I used to be William V., because, when I stepped onto the hallowed grounds of the SDMB, I thought that my username actually had to be a personal identifier. D’oh!
I chose my current username for its Tolkienesque goodness.
You’re looking at it, Spanky.
You must have ESPN or something. I just got back from the restroom. You’ll never guess my little guys nickname.
I started out using the name ‘Fat Angel’ which is actually the name of a Donovan song, but some folks ‘let me know’ that they thought this name was making fun of fuller figure folks, so I changed it to “Me!! Joe!!!” - that is, until I got fired from my dot.com job and ended up internet-less for about six - eight months. I reregistered under my current name, which since the subject has been broached, I am sick of and am thinking of changing…
Me too. But as a 99’er with less than 1000 posts, nobody would notice the difference anyway. 
I used to be Mayflower. Got tired of it and was granted my one name change (I changed it to a name that would reflect my love of singing).
I used to be Tretiak, named after the famed Red Army goalie and not the villain in The Saint
Fortunately for you, I don’t remember there ever being a Henderson.
The once and only Akira5822
I joined in late 1999 as mattk (or was it MattK? I can never remember, but there was another poster I got confused with).
xgxlx
Which used to be my name everywhere, but after some contemplation, I realized I no longer thought that X’s made everything cooler, and hadn’t thought so for some time. I still need to change my LJ name, though…