the only thing i abhor in usernames are numbers. unless you can really make it work i hate seeing names like 'pkmntrainer146' or something, bleh. but then i've run into considerable trouble with names online as well - which is why i'm so happy that PC is so lenient, and even allows spaces (and japanese characters! lol).
before when i couldn't think of a good name, my go-to was hiinotama, simply because it was never taken - because it's actually a misspelling of an unused word. now though i try to take 'blauweregen' whenever i can. it's dutch, literally translated means 'blue rain', but it's also the dutch name for the Wisteria plant, which i love (。 >艸<)
all this talk of old usernames is making me feel nostalgic haha