After first having my username on some random site a long while back I can say now that I can't wait for AG3. Right now I think Krios is a pretty cool one, although I can't exactly remember where I heard it. Wait, some other AGer already has it. Guess I'll have to think of another one...
I usually use something with one capital or two, never numbers, for example, one of my accounts is called CaptainBlackale. I usually call myself Masterforger or Captain something. Next time, though, I may go for something more medieval, like "LesCapitaine" or "Jarl" (pronounced "Yarl"
A "good" name is going to vary for person to person, but if I were to recommend ideas when trying to come up with a name, I'd say that over all it should be unique. Try to stay away from phrases and complete randomness; being a little random is okay, just don't go over the top. I'm a huge fan of picking something that you like and then seeing how it is translated into a different language. (I usually translate into Celtic, just because it's cool. XD )
Titles are neat too, as well as nicknames you go by in everyday life too. Just pick a style that you like. But please, stay away from numbers. If you have to put numbers on your name in order for it to be available, then I don't think it is unique enough.
im sorry guys but im dissagreeing with about 75% of these names. here are my opinions: -spikeabc [of course -nitroblast -so sexy its scary -steelforce -time2own the noobs -the champion -masterblaster -final stand -serial PWNER -room 4 one more -matrix tactics -this means war
thats possibly half my ongoing list. ik. i've been around these types of usernames.