Oriental people (that includes ethnic Chinese, Korean and Japanese people) are very particular about addressing elders. It comes with the entire mindset about having to respect people older than you. It is never acceptable to call an adult, or somebody who is of an older generation, or somebody of a senior position than you by his/her first name. It is considered to be very rude, and you'll very likely be critisised. Worse still, your parents could also be critisised for not having taught you manners.
I'll always use adults' surnames when addressing them. That is, Mr or Miss or Mrs So-and-so. If the situation calls for less formality, eg if that adult is a friend of your parents and you've known the person for some time, it becomes acceptable to use his/her first name, But, you'll still have to prefix it with 'Uncle' or 'Auntie'. That is, Uncle So-and-so, or Auntie this-and-that. Though the adult is not related to me at all, by calling them uncles and aunties I express familiarity, yet respect at the same time. As I've said, it is never acceptable to use their first names.
I found Karen's point about using first names at family reunions interesting, because such a situation would never happen in a Chinese family.
We don't have a generic term when refering to our parents' brothers (uncles) and sisters (aunties).
For example:
I'll call father's older brothers 'Bo Bo', but my father's younger brothers 'Shu Shu'. In addition, I'll have to call them by number, depending on age. Let's say my father has 3 older brothers, and I'm trying to talk to the 2nd eldest uncle. I'll call him "2nd Bo Bo".
What I call my uncles and aunties will depend on a number of factors, such as if they are older or younger than my parents, if they are my parents' brothers/sisters or if they are my parents' brothers/sisters- in-law. It'd also matter whether I'm referring to my paternal or maternal uncles/aunties.
Because we have such specific terms when addressing family members, there's never a confusion as to who you are trying to call.
I'm with Laura here; I have a hard time calling adults or people in senior positions by their first names. It just seems weird and unrespectful to me.
Over at the boards, I don't see you all physically, just the words you type. Hence, it's still possible for me to address you all by your first names (I have this illusion that everybody here is my age).
Now, if I were to meet... say... Wendy in person, I'll be addressing her as Ms Richards respectively. Unless she'd prefer the more familliar 'Auntie (Wendy or Richards)'. Then again, I won't feel strange calling her 'auntie' but she may find it awkward.
