simple 2 panel interior door. with a modern styled home I think either a 2 panel door or a flush door looks best, though in a pinch there are some great 5 - 6 panel doors that could work as well. but for me it's always best to keep it simple.
Paint Interior Doors Tips and tricks: Changing the color of an interior door can take a room from drab to fab. But too much contrast between the door and the wall can be jarring, warns Filian. If your walls are bright, choose a similarly lively color for the door.