in the older goddess-based religions, and the cultures centered around them, the priestess was really a little bit of everything.
she led religious rites, rituals, and celebrations. she many times acted as healer and also midwife. in her role as priestess, during rituals, she *was* the goddess, she literally became the flesh-imbodiment of the deity.
in her everyday life she was still respected highly. she was counselor, advisor, and confidante on issues both spiritual and secular. although she very rarely held any "formal" position, she was frequently consulted on matters involving running the village or community, and her word, if she was asked for it, was usually taken as the final say in matters. she was at once woman and deity, mortal and astral.
although the priestess role today is somewhat diminished, at least within pagan sects it is still a very important one. wicca (specifically gardnerian wicca) has the most well-defined priestess-role, and many solitaries and eclectics will still follow this progression to reach priestess status.
the priestess today again leads rituals, although she merely leads them, she does not really "become" the goddess. she also performs rites such as handfastings and weddings. (incidentally, many pagan priestesses are also ordained by the unitarian church as ministers, because this gives them the power to make pagan weddings *legal*. pagan marriage and/or handfasting is not recognized legally.) she also in many instances a confidante and is turned to for advice.
but today the priestess is more human, more mortal. she is a religious leader, but merely human as the rest of us. a thousand years ago, you'd *know* if you met a priestess. her reputation would have proceeded her, and if it hadn't the mere reverence her townspeople gave her would make it clear. today, except at ritual, you can't pick the priestess or preistesses out of a pagan crowd, or any *other* crowd at all. they're committed and dedicated. but they're just normal people underneath it all.