I would second the technique of whirlpooling your wort when cooling and then dumping it into the fermenter using a strainer. The strainer really helps keep most of the trub out of the primary and also gets the wort nice and aerated. Hops in the primary are not necessarily a bad thing, but one that I like to avoid so I don't have to worry about them when racking later down the road.
Yes, you can also use a hop sack at the bottom of your siphon, however, a word of advice: The bag gets clogged after a while. You'll notice that your flow rates slow down due to the trub stuck all around the bag. I don't use this anymore, but have in the past.