I feel as though the topic title should be a bit more descriptive as to what the topic is about.
I use : p or >:I a lot to point out that I'm joking or being sarcastic, and I use XP to reinforce the fact that I'm in a friendly lighthearted mood.
I don't think I've ever used an angry face when I'm actually angry at something.
I never use ; ) because it either sounds snarky or flirtatious and I've been told by several female friends that it makes them feel uncomfortable when guys use it.
I also never use ^^ or any variation because it feels too cutesy and out of character for me.
With that said, it depends on how the programs reformat these emoticons. For example things that I wouldn't normally use like ; ) look more acceptable as
Skype completely ruins the : p emote and I feel like our forums make it look kind of dumb too