If my family gets me a huge service, then they are inconsiderate dickwads. They have specific instructions to not waste thousands of dollars on bullshit like a funeral. If they feel the need to waste money, I've told them to buy a speed boat or something instead, since at least that would serve SOME purpose.
As for my body, I want absolutely anything/everything to go towards helping people, or to science, or to both. Fuck, if I could donate every last drop of blood as I took my last breath, I would.
There is no reason for anyone else to not do the same in this day and age, and I consider it a moral imperative to donate all of your organs and tissues. If you don't, you're either uneducated, or an asshole, or both.