Just found a gold mine if you're interested in historic VM. Documentary Educational Resources is releasing DVDs from the Screening Room Series, which includes John Whitney, Brakhage, and others. In the Whitney, http://www.der.org/films/screening-room-john-whitney.html
John talks about his work and plays several films, most with music (Matrix, Permutations, et al.)
Also received Brakhage and Breer today but haven't had time to check them out.
Not a lot of money for home use, but institutional is really expensive.
Best.
d.