OK, now I'm depressed: recent health reports say that tuna for sashimi can contain high levels of mercury and be dangerous to eat.
Then again, I don't think I'm going to stop eating sushi/sashimi. The Japanese haven't stopped either.
By the way, tuna sashimi is delicious (La Parisienne and I occasionally indulge in spicy tuna rolls), but my favorite raw fish is actually salmon. A really, really good salmon is meltingly soft, gorgeous in color, and, oh, so yummy!