There's not much use for dark matter - this kind of stuff is strictly in the realm of big-picture cosmology, astronomy, and fundamental physics research - mars rovers, telescopes, the sloan digital sky survey, the Large Hadron Collider.... none of these things are expected to produce some new material that will make life better, but they are hoping to expand our understanding of the universe.
Then again, sometimes you get a lot of practical stuff by accident along the way in the pursuit of "pure science". Think about all of the good stuff that came out of the space program - computer technology, velcro, Tang, dried ice cream <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" /> <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" /> <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />
Heck, the World Wide Web and web browsers were invented at CERN, which was a particle physics lab that was doing research into fundamental particles, not because they thought they could find an industrial use for Quarks and Gluons, but because they wanted to understand the universe a little bit better.