🙂 Your basic smilie. This smilie is used to inflect a sarcastic or joking statement.
😉 Winky smilie. User just made a flirtatious and/or sarcastic remark.
🙁 Frowning smilie.
:-I Indifferent smilie. Better than Frowning but not quite as good as 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 somewhat less common ones:

(-: User is left handed
%-) User has been staring at a monitor for 15 hours straight
:*) User is drunk
[: User is a robot
😎 User is wearing sunglasses
B:-) Sunglasses on 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 juust made a wry statement
:-* User just ate something sour
:-)~ User drools
:-~) User has a cold
:’-( User is crying
:’-) User is so happy, s/he is crying
:-@ User is screaming
:-# User wears braces
:^) User has a broken nose
:v) User has a broken nose, but it’s the other way
:_) User’s nose is sliding off of his face
:<) 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 some other religious office
`:-) User shaved one of his eyebrows 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)
😛 Nyahhhh!
:-S User just made an incoherent statement
😀 User is laughing (at you!)
:-X User’s lips are sealed
:-C User is really bummed
<|-) User is Chinese
<|-( User is Chinese and doesn’t like these kind of jokes
:-/ User is skeptical
C=:-) User is a chef
@= User is pro-nuclear war
*<:-) User is wearing a Santa Claus Hat
😮 Uh oh!
(8-o It’s Mr. Bill!
*:o) And Bozo the Clown!
3:] Pet smilie
3:[ Mean Pet smilie
d8= Your pet beaver is wearing goggles and a hard hat.
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
K:P User is a little kid with a propeller beenie
@:-) User is wearing a turban
:-0 No Yelling! (Quiet Lab)
:-: Mutant Smilie
  The invisible smilie
-) User only has one eye
,-) Ditto…but he’s winking
X-( User just died
8 🙂 User is a wizard

Note: A lot of these can be typed without noses to make midget smilies.

🙂 Midget smilie
:] Gleep…a friendly midget smilie who will gladly be your friend
=) Variation on a theme…
:} What should we call these? (what?)
🙂 Happy
:> what?
:@ what?
😀 Laughter
:I Hmmm…
🙁 Sad
:[ Real Downer
:< what?
:{ what?
:O Yelling
:C what?
:Q what?
:,( Crying
] Hugs and
:* Kisses
|I Asleep
|^o Snoring