If I can't donate my organs and tissues; I'd really be interested in donating my whole body to science or to a surgical college as a teaching tool.
I like green burials, but only if there's something left to bury! Being wrapped in an unbleached, plain, off-white linen shroud with goodbye messages written on it at the service seems like an awfully nice way of getting put in the ground. Much better than a concrete sarcophagus.