I recently had a stump about 40" in diameter ground up. I had to remove about 4 wheelbarrow loads of wood chips afterwards to get it level. I put some grass seed and some Miracle Grow garden soil on it.
I did the same to another area a few springs ago and by mid summer you couldn't tell where it was.
Also, I've placed half of a 55 gallon barrel around a stump, poured in about 5" of charcoal and lit it up. It takes 4 or 5 applications, but it will eventually burn it down to ground level.
