I'll freely admit that I'm a snob about heels.

I hate them. I don't hate the dancers, and I know at least one of the reasons for the heels...but it makes me annoyed to watch dancers dance in heels.

The things that I usually notice most when a dancer is wearing heels are that they have a swayback (not necessarily a huge one, but still, not a neutral pelvis), they don't move as smoothly, and they look like they are more nervous about falling.

I'll caveat this with that I've seen Egyptian dancers (actually from Egypt, not just the style) who do all their practicing and performance in heels, and they don't look uncomfortable or nervous about falling. I still don't enjoy their dancing as much, but you can tell the difference between the dancers who only perform in heels versus the ones who practice and perform in them.

i think if you can keep safe dance posture in them and your like it, then go for it, but you do have to PRACTICE in them all the time, it is harder to keep posture because of how they shift your weight and encourage you to lock your legs, which hits your pelvis, which hits your back, etc. you would always be fighting the heels to keep yourself safe.
my dad is a chiropractor and is always talking down about high heels, that they're bad for you. i think it's possible to be mindful and correct what they do to your posture, but very hard and i don't think it's worth the risk if you're dancing and practicing regularly enough, it would accumulate to too much time in heels.
not to mention that you have to get dance specific shoes, which can cost, because of the risk of walking shoes (and not-for-walking ^_~) shoes breaking under the stress of dance, some serious injury potential there.

I prefer the barefoot look, too, and I definitely prefer dancing barefoot (which is probably related to Fariha's point about the necessity of *practice* to maintain a safe dance posture...). But, I have seen some gorgeous belly dance in heels, and it doesn't bother me when dancers wear them as long as they do it correctly. It's definitely mostly about maintaining posture. Dancing en releve shouldn't change your posture or your ability to perform all of your movements, nor should heels. I think the Indigo dance well in heels because they maintain their dance posture well, not just because of the style they're performing or the shoes they're wearing.

And, though I do prefer the barefoot look, sometimes dancers just need to be in shoes (dirty restaurant floors, etc)...and personally, I really dislike the look of Roman/Hermes sandals, especially with glitzy oriental/cab costumes.

I think heels often get a bad rap among us belly dancers (especially Americans) because it seems like a "less authentic" look...I definitely used to think so! But then you watch Samia Gamal, or Tahia Carioca, or Nadia Gamal, or even look at old pictures of Ghawazee dancers, and they all wore heels (not always ballroom-style heels, but heels nonetheless). It's practically mandatory for Lebanese style.

I still like barefoot better, though.

Heels, never, not for me anyways. I prefer bare feet all the time, even when I am not dancing. I will have to buy those ballet slippers soon though for a November show, and don't know if I can adapt to them even, never mind heels. Ekks.

some good feedback! as for ballet shoes, pick carefully as I tried three or four kinds. JJ's (they have two elastics each show that cross over the top of the foot to keep them on) can be a little sloppy, but are one of my fav for casual dancing. Beware the "real" ballet beginner shoes where the leather draws over the front of the foot and joins a little 'pad' right under the ball of the foot. Ouch!! A real dance supply store will be able to help you choose shoes.

This is an interesting topic, worthy of further debate from many angles.
When I was younger I indulged myself with burlesque. The standard at the time was 5 inches with no platform. Platforms moved in and made the height of 6 much more comfortable, what with an inch or more cushion under the ball of the foot. Then eventually the height moved to 7 and beyond, adding a stilheto toe shoe/pointe shoe.
Obviously as stated in a comment above, these heels emphasize the tush with the forced shift of the pelvis and does change the center of gravity for any movement. An added restriction would also come from additional straps, height of boot tops, etc. All having to be brought together in practice before hitting the stage.
Ah ha!
There you have it- the stage.
Not all venues have stages.
At a hafla or workshop or venue with a stage, it can be taken for granted that there is a properly cared for dance space.
But it wouldn't be wise to take anything for granted where the health of your feet, one of the fundamental structures to be able to dance is concerned.
It is always wise to have some kind of shoe at the ready to perform in. Practice in them.
Outdoor stages, where the elements have had their way with the stage are also cause for concern.
Half sole and Hermes sandals by capezio are wonderful for street, no stage, and out door stage performing, as well as getting to and from in costume.
We have to take care of our feet. Extreme care. To be brutally honest, they harbour staph.
Pumice, nail files, lotions.
And extreme heels can pinch bones into bunions and force arches out.
Personally I prefer to belly dance barefoot. But I'd put shoes on in a heartbeat if I was performing in a tooo communal area.