I think that both terms "media" and "new media" are very much
conventional    in  the sense of how we use them in our professional
communication. I personally stand for an empirical approach to their
definition since they don't have singular commonly shared meanings, and
for the majority of people are usually associated just  with the mass media.


 > I don't think the term new media art is very useful at all. It determines
 > difference according to means rather than intent or context.

I quite agree with this point.
I'm convinced that while talking about "media art", we, or at least most
of us, mean a new form of art determined by its medium or tool (by
analogy to painting, etc). Under media in this context we rather mean  a
complex set of modern technologies for production and reproduction,
distribution and receiving, use and representation of information. In
this regard the term "new media" is basically an extension of the term
"media", and no more than just an emphasis of  the distinction
between "older" and "newer" generations of media.
Thus I see it as  a rather supplement of the term "media" which doesn't 
bring any new substantiveness     .

 > inclusive engagement, I think you will agree that the actual practice (in
 > terms of intent, context and instrumentality) is too diverse to be
regarded
 > as a consitituted movement - or even a general dynamic as broad as
the terms
 > Modernism or Romanticism were able to encompass. The practice we see all
 > around us is, again, too diverse to be tucked under even those broad
 > umbrellas.

I absolutely agree that you can't talk about "media" or "new media"
component in definition of a particular cultural or art form  as a label
which helps us to distinct "a general dynamic", as Simon Biggs put it.
Both media as a cultural phenomenon and media art are  too heterogeneous
for that. Although if we look at the ptoblematics of media/medium for
the media art in a perspective of art history, then it is obviously
totally new set of questions for the aesthetics informed consequently by
the problematics of  media as part of socio-politico-cultural relationships.

I think it would be more productive to look at the entire problem of
definitions (or taxonomies?) of media/new media practices very
contextually and empirically, then it will be easier for everybody to
deal with them. Why do we need endlessly ask ourselves” what is media
art?" while we all know, even if it is intuitively, what do we mean?
The same with "what is art in media art"? Since we call it art and not
something  else, does it make big practical sense to go into endless
speculations about it? Just look how far  are philosophers-aestheticians 
   with
the similar questions - they are still discussing painting and can't
resolve  them:)