There's a lot to the subject of vultures. It's one of my two totem animals, although I'm not really into the dining experience aspect.
To touch on two of the things already said
They are in the Order of raptors, to which eagles and hawks also belong
There are probably several reasons for this wing-spreading behavior, including warming or cooling the body, exercise, pleasure and courtship, but hygiene is almost certainly at the top of the list. Hygiene is also the reason for their bald heads.
Other tidbits:
Vultures have the most efficient means of travel of any animal on Earth, measured in calories expended per pound per mile. They are the most glorious flyers, although the most dynamic is the falcon. The condor tops the efficiency scale.
In parts of the Himalayas the human dead are cut up and fed to the vultures as the main sacred funeral rite
A very interesting thing to do is find the tree that the Wake (the name for a flock) roosts in at night and be waiting at the base of the tree when they come home. They will circle you up close and silently for a long time, so its uncool and rude to do this for too long. There will be feathers there too.
There is an Egyptian vulture goddess named Nekhebet, see:
http://en.wikipedia.org/wiki/Nekhebet
If I ever did a Tarot deck, the ten of swords would have five vultures circling high in the sky, watching for signs of life to erase.
I once saw seven vultures and eight bald eagles sharing the same dead elk.
I wouldn't dismiss looking at them as a symbol of the beauty that we overlook, because it isn't glamorous enough for our species-centric tastes.
I continue to be dismayed at the people who made and updated the Medicine Cards deck and still haven't shown enough wisdom to include the vulture (or the lowly vole). I just can't trust the narrow minds of people like that.