Aerith - it's the avatar that does it, but other than that I feel that she has that positive outlook and slightly bubbly attitude, all the while maintaining that snappy little edge that just completes the whole picture
Selphie - I feel like she's always there for events, often organizing them in order to engage this little community we have (as seen in this very topic )
Queen - mostly because she just feels like she has a lot of smart things to say

Now to close this little circle we have going on, I nominate:

Wolf Kanno!