What is the most expressive part of your dog?

Definiately the eyebrows.

 Her ears. Can you tell how she feels in this pic?

Buddy: ears, eyes and face.  I can tell if Buddy is happy or feeling bad or just feeling like the bottom of the totem pole by his ears, eyes and face.

Heidi: vocals.  I can tell whats up with her by her different barks, growlies (play or not).

Bruder: ears and tail.  But, he is pretty vocal too.  Just not quite as diverse a "vocabulary" as Heidi. 

Kenya: Mouth.  I *always* tell this to new people, "If the mouth is SHUT, please leave her alone.  This means she is alert and probably anxious and tense.  If the mouth is OPEN like a smile with the tongue a bit out, you may pet her.  This means she is content and relaxed."  Also, since she doesn't growl, she gives off calming signals and "go away" signals with her mouth like yawning, licking lips, showing teeth, etc.

Coke: Ears.  Coke has big, soft, floppy ears but they lay back, perk up, come forward depending on his mood.  When he's running around playing, they fly up in the air.

Nikon: Vocals! Nikon barks, grunts, howls, growls, whines, chatters....he vocalizes *everything*!!  "Speak" was his first and most reliable command.  He can also "whisper", "pass auf", "revier"...all various commands involving some type of bark. 

 difficult to pick one body part - definitely not his mouth

his eyes and ears are very expressive but I can tell from a distance what he is up to by what his tail is doing so I'll go with that LOL

River:  His bark - very vocal much like Nikon.

Brooke:  Her ears and eyes

Hailie:  Her tail and ears.

Chyna:  Her ears.  I can tell exaclty what her intentions are by how she's holding her ears.

Bevo:  His mouth.  He is generally smiling, & has an open mouth.  If his mouth is open, he's happy, & ready to interact with others.  If his mouth is closed, he's focused on something, & is best left alone. 

Brinxx:  Her posture.  She does all kinds of funny things, & you can tell what kind of mood she's in by the way that she's standing. 

Shooter:  His bark.  He talks.  A LOT!

Schatzi:  Her eyes.  She knows exactly how to work me to get what she wants (to be held & snuggled) just by what she does with her eyes.

Brutus:  His silly head tilts.  He's hilarious.  He twists & turns his head all over the place. 

Angel:  Her tail.  If it's curled over her back, & waggy, she's happy.  If it's not, then something is wrong.

Cher:  Her ears.  For now, they are big, floppy & goofy, but she still works them.

T-Bone definitely talks with his ears. He does this adorable ears flattened to the side begging thing when he wants a cookie.

Moca: her butt (the little stub of a tail means she uses butt more than tail)

Jason: Ears (although his eyebrows are a close second.)

With Rocky its the eyes and tail.

With Hot it is lots of things.... tail up and curled slightly means someone is in his area that should not be , his paw..mostly the right paw always goes up when leaning for petting, I mean always.  He smiles alot big smiles.  If he is wanting Daddy to give him some food he lays his head between his paws and looks up with those big brown eyes.   Now he is a talker too....certain noises mean someone is here, some mean I'm here now so you can pet me instead of Mom....lol,  he will go out to the yard and just bark when he thinks its time for Rocky to come home, he will just start ooooing and arrrfing when he is just telling you something.   LOL...I know you must think I am crazy but if I can ever get his dog talking down we are going to go on the road and make a million :)

 I have really enjoyed reading everyone's replies!

 Ari's is definitely her facial expressions. You can tell instantly with a look from her what she is thinking/feeling, or more importantly about to get into mischief! She has one look which the SO and I warn each other about, if we see it. She had her head very slightly down, she raises her eyes up to you (so you can see her whites underneath) and her tongue is very slightly protruding. It's her, "I'm about to lose all semblance of sanity and wreck havoc in 0.02 seconds".

the_gopher

It's her, "I'm about to lose all semblance of sanity and wreck havoc in 0.02 seconds".

ROTFLMBO!!!!!!

shadowsgin

ROTFLMBO!!!!!!

You only laugh because you don't have to see that look and just know you need to find a way to refocus her RIGHT NOW, or protect your extremities. This look is followed by a butt tuck zoomie and ankle biting (please see my user icon photo; this picture is the direct result of above mentioned look. She went for the ankles and I pinned her with my feet). As she's *cough* matured some, redirecting with a toy has gotten much easier.

My favorite look is the "OMG I'M SO HAPPY MY EYES ARE GONNA BUG OUT OF MY HEAD". It's for this look alone, that we allow her to live.

I am enjoying the other replies to!

(Especially about Ari's "look" LOL)