:-)     Your basic smilie. This smilie is used to inflect a sarcastic or joking statement, since we can’t hear voice inflection online.
;-)     Winky smilie. User just made flirtatious and/or sarcastic remark. More of a “don’t hit me for what I just said” smilie.
:-(     Frowning smilie. User did not like that last statement, or is upset or depressed about something.
:-I     Indifferent smilie. Better than a frowning smilie, but not quite as good as a happy smilie.
:->     User just made a really biting sarcastic remark.  Worse than a :-)
>:->    User just made a really devilish remark.
>;->    Winky and devil combined. A very lewd remark was just made.

Those are the basic ones.Here are some less common smilies:

(-:     User is left-handed.
%-)     User has been staring at a green screen        for 15 hours straight.
:*)     User is drunk.
[:]     User is a robot.
8-)     User is wearing sunglasses.
B:-)    Sunglasses on top of head.
::-)    User wears normal glasses.
B-)     User wears horn-rimmed glasses.
8:-)    User is a little girl.
:-)-8   User is a big girl.
:-{)    User has a mustache.
:-{}    User wears lipstick.
{:-)    User wears a toupee.
}:-)    Toupee in an updraft.
:-[     User is a vampire.
:-E     Bucktoothed vampire.
:-F     Bucktoothed vampire with one tooth missing.
:-7     User just made a wry statement.
:-*     User puckered up, either from something sour        or for a kiss.
:-)'    User drools.
:-')    User has a cold.
:'-(    User is crying.
:'-)    User is so happy, s/he is crying.
:-#     User wears braces.
:^)     User has a broken nose.
:v)     User has nose broken the other way.
:<)     User is from an Ivy League school.
:-&     User is tongue-tied.
=:-)    User is a hosehead.
--:-)   User is a punk rocker.
--:-(   (REAL punk rockers don't smile.)
:=)     User has two noses.
+-:-)   User is the Pope, or holds another religious office.
':-)    User shaved one eyebrow off this morning.
,:-)    Same thing...other side.
|-I     User is asleep.
|-O     User is yawning/snoring.
:-Q     User is a smoker.
:-?     User smokes a pipe.
O-)     Megaton man on patrol! (Or else, user is a scuba diver.)
O :-)   User is an angel (at heart, at least).
:-P     Nyahhhh!
:-S     User just made an incoherent statement.
:-D     User is laughing (at you!)
:-X     User's lips are sealed.
:-C     User is really bummed.
:-/     User is skeptical.
C=:-)   User is a chef.
#=      User is pro-nuclear war.
:-o     Uh-oh!
(8-o    It's Mr. Bill!
*:o)    And Bozo the Clown!
3:]     Pet smilie.
3:[     Mean pet smilie.
E-:-)   User is a ham radio operator.
:-9     User is licking his/her lips.
:-6     User is braindead.
[:-)    User is wearing a walkman.
(:-I    User is an egghead.
<:-I    User is a dunce.
#:-)    User is wearing a turban.
:-0     No yelling!
:-:     Mutant smilie.
.-)     User only has one eye.
,-)     Ditto, but s/he's winking.
X-(     User just died.
8 :-)   User is a wizard.
C=}>;*{)) MEGA-SMILIE: A drunk, devilish chef with a toupee in an updraft, a mustache, and a double chin.
NOTE: A lot of these can be typed without noses to make midget smilies.
:)      Munchkin smilie.
:]      Gleep…A friendly Munchkin who will gladly be your friend.