Did you, by any chance, work in the Radio business in Atlanta?
I’ve been called “Skip” in some form or another for the past 12 years now; so, even though it’s not my real name, I’ll answer to it well enough.
And while user names are somewhat silly to say aloud (in a lot of cases), I feel strange using real names. Baker will almost always be Baker to me–even though her first name is easy to remember.
When I started dating auntie em I felt strange calling her by her first name. And I still want to refer to her as 'em at times.
I’m another one for whom it’s not a problem … I tend to use screen names initially (after all, it’s how I actually relate to these … people), but move towards real names as I get to know them IRL. Stay with screen name if 1) they don’t give a real name or 2) they have a very definite online “personality” that, well, registers them under the screen name to me. Try to move towards the real name if the screen name is 1) unpronounceable or 2) too silly.
I’d probably refer to myself by my screen name - well by “Missy” - now that I’m married, my real name is like something outta “Petticoat Junction” and causes me NO END of embarassment. As does my husband at times. 
Your name is “Uncle Joe?”
Screen name first, the real names for me. It’s easy and with a small group (such as us IndyDopers), imparts familiarity fairly quickly. Although I must admit, I don’t remember Munch’s or AskNott’s. “Munchy Honey” is way more fun to say anyway!! And Howard Juneau is cool enough to stand on it’s own.
I have a novel approach.
those I know well enough, I call them by their real names when addressing them, but their Screennames when referring to them in conversation with other people.
Me, I’m pretty much Twisty to everyone 
I’ve been meeting folks under various user names for years now. (No, not from this board) I like being referred to by user name, and like using user names; it’s fun. But I’d always give my real name in person if asked.
It’s always disappointing when you meet someone from online and they say “Hi, my name’s Bob.” It’s as if they want to distance themselves from their online personality. No fun whatsoever.
I’ll usually introduce myself by screenname (or just TP, since as many people know me by that shortened form as they do by TruePisces) and then give my real name. I’ll answer to either. When talking to or about other Dopers, I change out screennames and real names fairly interchangably. However, I’ve noticed that the real names seem to become more common the more I interact with them off the boards.
Everyone calls me Ginger or Gingy. No, it’s not my name, and nobody can seem to remember my name.
Weirddave is always weird, and always Dave. I call him Dave.
I call you by your given name: Hellwig’s Fan. 
My friends (both of them?) call me Bruce Daddy irl. However, a witty few have changed it to B. Diddy.
Don’t sweat it. I like being Balance. (And I can’t remember your IRL name either…)
From my IRC days and video conferencing internet chats, people have just shortened my handle to Mana. I’ll respond to my RL name or my nick but since my RL name (mike) is so damn common simplying asking for mike isn’t very helpful.
Just call me mana, bad mana.
lol now it would be hilarous if i could find someone to call my by my username in real life…
I’ve always been called by my full 5 letters name. Although lately, some friends found a way to shorten it to 1. hehehe
or should i stick to the jabka (Polish for little girl-frog) that my mother used on me when i was very young??
Too many damn Johns in this world (except when you really need one). I answer to “Nurse” more than “Carmen” or “NurseCarmen”. My nickname in College was “Padre”, so if you throw that in, I’ll be thouroughly confused.
Well, I read the name in a book and it’s a Welsh word so I have no earthly idea how it’s actually pronounced. But I say it, as Rue put it, like Elmer Fudd would say dryer. And like Ellen said.
I like using it because it’s distinctive, unlike my real name.
And see? People talk about me this way!
As for using others screen names, I’m really bad at names and it’s taken me a couple of years just to remember the pseudonyms. I’d never get anyone right if I tried it with their real names.
SN and IRL name close enough…and I answer to “Evil Beeyotch” mosta the time…
Dee Dee
I introduce myself by my SN, then my real name, and then everyone calls me “Lux” or “Luxie” for the rest of the night.
Sometimes I find it odd to be answering so reflexively to a name that doesn’t appear on my birth certificate, but most of the time I don’t even think about it (see relevant adverb in first clause).
For other dopers, I think I remember like 5 or 6 real names of those I’ve met. Everyone else gets the screenname.
Most everyone calls me Andy at dopefests. Can’t imagine why…