I'm with Clinton on this one. Organ donation should be an opt out rather than opt in so, unless you have any seriously good reason why not, organs should be up for grabs and noone (not even next of kin) should be able to change that. I do like the idea of using the ashes to fertilise a new planting.
A few places offer ecofriendly funerals here but a lot of directors still want to sell the wooden box with ornate brass fittings. They didn't find it at all amusing when I told them my mother wanted to be put in a cardboard box from Tesco!!