You will need the curtain rods and the ceiling brackets. If you'd like to dress the rods up a bit, you could even have finials at the end of your rods. In the corners, the rods can either 1) butt up against each other, 2) be separate rods and not touch or 3) be mitered so that the ends match up perfectly.
As far as the curtains go, you could go casual and get sheers. You could go with a more romantic look and get a floral or toile fabric. If you want to go super-formal, you could get silk or velvet curtains.