Ah, now I am reminded that the first time I saw the username Enola Straight, I got the giggles.
Hypno-Toad always conjures up funny images and makes me giggle.
I have a soft spot for John Carter of Mars; I love those books. And the poster behind that username is very much a gentleman.
Slihy Tove, Dijon Warlock and Podkayne (because I loves me a good Heinlein reference).
I once knew a fine soul named Rex Havoc. Wish I could track him down. In the way back machine, we were two Suns on a BBS named Baudville (which was also clever)
Here, I adore the names GoYouBigRedFireEngine, Left Hand of Dorkness, the punny folk, Shirley Ujest, Lucy In Disguise etc., Least Original Username Ever, SurrenderDorothy (I want to be just like her in my 2nd childhood) Stranger On A Train, and of course, one after my own heart, MsWhatsit.
I loved Don’t Poke the Bear, Dad!
Found her!
Again, iamthewalrus(:3= because that is the COOLEST emoticon. I used it on another board as a sig for a while. 
HappyScrappyHeroPup
Since I FINALLY watched the movie… InigoMontoya is a very interesting choice.
Don’t know if he’s still around… 1010011010 always intrigued me in a math geek kind of way…
There’s probably more…
There was a user by the name of Holy shit I like pie!, but sadly he/she was banned before ever posting.
I always love saying WOOKINPANUB’s name out loud…
mm
The Chao Goes Mu
always provides a chortle
Happy Clam also, but I may just have a particlularly feeble and slightly dirty mind
Fat Bald Guy, Quasimodem, Rue DeDay, Shirley Ujest, NoClueBoy, Guinastasia, jinwicked, Kn*ckers, FireUnderpantsBoobs
“What’s your favorite …?” threads belong in IMHO.
I’ll move this for you.
Cajun Man
for the SDMB
I like Batsima Belfry and Patty 'O Furniture.
Earl “Snake Hips” Tucker and **My Darn Snake Legs ** always get chuckles out of me.
I also enjoy Filthy Beast of Meat and Hair.
My all time favorite name was Soylent Gene. I wonder if he’s still around.
He may need to change his name.
My favorite username just posted in #34–badbadrubberpiggy, partly because she sounds like my evil twin.
Anybody mention Imthecowgodmoo yet?
I came in here to post those two
Exapno Mapcase definitely. Johanna explained it once long ago and I’ve loved it ever since.
There are more, I will try to remember and post later.