-.- Annoyed (Used in anime on occasion)
-.-;; Annoyed/Embarrassed/Awkard Position (Note the drops of... sweat? Used in anime more often than just the annoyed. Use more ; to emphasize.)
-.-* Annoyed/Pissed (VERY commonly used in anime. Normally appears on the side of the forehead. Usually accompanied by someone getting bi***-slapped. Use more * to emphasize.)
:? Confused (Rarely used)
:S Confused/At a loss (Used when you can't really think of anything to say.)
@.@ Dazed/Dizzy/Boggled (Self-Explanatory, used when someone is shell-shocked by something. Also used in anime, but you just see spirals instead of eyes.)
X_X Dead (Self-explanatory, no?)
X_x Dead/Shocked (Used more when you are shocked to death, than just dead.)
>:) Evil (note the eyebrows on the smiley face, denoting an evil intention)
:( Frowny (2nd most commonly used)
:[ Frowny (Rarely used.)
:} Happy/Crying (Note the quivering lip.)
^.^ Happy/Hyper (Commonly used by... ME. Can be used in place of the smiley.)
^.^;; Happy/Hyper/Awkard Position (Used... when trying to hide feeling of awkard-ness from a happy state. Use more ; to emphasize)
^.^* Happy/Pissed (Used when trying to hide the Pissed emotion from a happy state. Use more * to emphasize)
=D Happy/Grin (Same as :D)
:D Happy/Grin (Used in conjuction with lol, but not necessary or common. Used often by self)
:| Neutral (Used when you just feel that... "Meh" feeling about something.)
=| Neutral (Same as :|)
>.< Ouchy (Eyes squinting inwards to denote pain or virtual pain)
=( Sad (Same as :(, only it seems to put use more emphasis.)
~.~ Sad/Crying
:{ Sad/Crying
;P Sassy/Sticking out Tongue
O_O Shocked (Eye popping shocking goodness! Used to emphasize shock more than O_o)
:O Shocked (Lesser form/Parent of the O_O. Use this when you want to lessen the emphasis)
O_o Shocked/Scared/Bewildered (More commonly used than O_O)
_._zzz Sleeping (One of my own I think...)
:) Smiley (Most commonly used)
=) Smiley (Used less often than the :) smiley. Same damn thing.)
:] Smiley (Rarely used.)
:P Tongue (The P is the tongue... use whenever you feel appropriate, like after saying something stupid, or when you would wave your tongue in an offensive manner)
=P Tongue (Same as :P)
:\ Undecided/Unsure/Slightly Nervous
=\ Undecided (Same as :\)
;) Wink ( It's winking...)

Feel free to submit more!