Cremation. "Burial in the ground" is derived from an old belief that the "body will rise up to the spirit" come judgment day. Can't believe that.
"Burial in the ground" just consumes valuable real estate. Cremation is a good way to recycle!

Cremation for me. I told my kids I'd they dressed me up and put me on display I would find a way to haunt them the rest of their lives.

"We couldn't decide between cremation and burial at sea. So we had him poached."

Up the chimney for me. I've seen the grief that my ex mother-in-law's grave caused between the family. Arguments over who was entitled to put flowers in which pot. Arguments over whether or not the plot was being properly maintained. Arguments when my ex wanted to shorten the grave (grass over most of it) but her grandmother didn't. And the constant obligation to visit, for fear of being all of the callous bastards under the sun as far as the rest of the family was concerned.

I don't want to be that kind of burden on anyone once I'm gone. So it's up the chimney for me. They can plant a tree or put my name on a park bench, if they feel like it. I think you can remember the dead without visiting the site where their body was disposed of.

Full viking funeral. Put my body on a wooden boat, set it on fire, push it out into the open sea and let it burn and sink

Depends on who is on the receiving end of the service.

I would really like to just have my dead body placed in a local bay. Not legal. The reason would be to feed that which I could, have what ever sunk into the sand and offer up nutrients for whatever is there in the future. As that is probably not going to happen I would go for cremation and then spreading the ashes into the same bay.

Donating my body for organ harvesting. Or science or forensics.