Cardinal Ratizinger in his excellent THE SPIRIT OF THE LITURGY:
"Dancing is not a form of expression for the Christian liturgy. In about the third century, there was an attempt by certain Gnostic-Docetic circles to introduce it into the liturgy. ... The cultic dances of the different religions have different purposes--incantation, imitative magic, mystical ecstasy--none of which is compatible with the essential purpose of the liturgy. ...
"It is totally absurd to try to make the liturgy 'attractive' by introducing dancing pantomimes (wherever possible performed by professional dance troupes), which frequently (and rightly, from the professionals' point of view) end with applause. Whenever applause breaks out in the liturgy because of some human achievement, it is a sure sign that the essence of liturgy has totally disappeared and been replaced by a kind of religious entertainment. ...
"I myself have experienced the replacing of the penitential rite by a dance performance, which, needless to say, received a round of applause. Could there be anything further removed from true penitence? ...
"None of the Christian rites includes dancing. What people call dancing in the Ethiopian rite or the Zairean form of the Roman liturgy is in fact a rhythmically ordered procession, very much in keeping with the dignity of the occasion."
From the Congregation for the Sacraments and Divine Worship:
"[In western culture] dancing is tied with love, with diversion, with profaneness, with unbridling of the senses: such dancing, in general, is not pure."
"For that reason it cannot be introduced into liturgical celebrations of any kind whatever: that would be to inject into the liturgy one of the most desacralized and desacralizing elements; and so it would be equivalent to creating an atmosphere of profaneness which would easily recall to those present and to the participants in the celebration worldly places and situations."
Sometime back, in the combox of the blog The Cafeteria is Closed, I was involved in a lengthy debate with someone using the name "white men can't dance" who claimed that the rejection of liturgical dance was European bigotry. I pointed out that ancient European (pagan) cultures had a tradition of dance in worship and that this was not "inculturated" by the Church. It is not about cultural superiority, rather, it's about decorum.
Dim Bulb comment to Cathy's "Abomination of Desolation" post