Here's a gorgeous series of Mark Langan's work, from corporate logos to abstraction. The material: corrugated cardboard, and it's executed beautifully.
Take something that's obsolete, use it for mixed media art, and presto, you have the art of Nick Gentry. From VHS tapes to 3.5" 1.4 mb floppy diskettes, Gentry is giving useless objects a purpose again.