This is a common misunderstanding. Sushi is anything with vinegared rice. There's even vegetarian sushi. What most people in the West think of as sushi is actually sashimi (usually raw fish/seafood, though some like tako can be cooked because of the consistency when raw. I also hear that there's non-seafood sashimi, but I've never tried it).
OT, sashimi is one of my favorites. Of all sashimi, I prefer maguro/toro. Very few places in my area properly prepare it, though. Only two places that I have tried actually taste fresh.
Takoyaki is another. Again, only a couple of places in my area make it decently. The other places it's like chewing on rubber.
