Jedi
The Jedis killed by the Clone Troopers were completely surprised (no premonitions, I guess) and outnumbered pretty much hundreds to one in each case. So it goes.
I only saw the movie once, but I recall Yoda being highly disturbed when the Jedi were killed.
Palpatine's attack also depended on surprise. It was established in earlier movies that the Sith had the ability to shield their true nature from the rest of the Jedi.
Trivia: The Jedi kid who cleaned up a bunch of enemies before falling himself, on the landing dock where Bail Organa was waiting by his ship, was played by one of Lucas' sons.