The Poly your using will determine the sheen or gloss of the floor. Most come in satin, semi-gloss or gloss. I like to do my 1st to coats using a High GLOSS finish then top coat with Satin or semi-Gloss. I was told a while ago that the gloss Poly has more Polymers therefore it fills grain better. I just think it gives the floors a deeper look thats why I do it that way. Here's a pic of my current project. It only has the 1 coat of Poly-urethene on it so far.
other pics can be seen at new wood flooring
Good luck with your Floor. They can be a lot of work