1the above list is just the basic for your bedroom. you might want to add a quilt to go along with your bed sheets if you are a person who gets cold easily
2you should always keep a set of sheets(twin or full) for your guest so you can cover your couch and they can sleep easier and feel more welcome.
3i find for this purpose i have dark sheets on fitted for the bottom and a flat for them to cover themselves. i also keep two blankets on hand for my guest as they too may get cold easily. I keep these blankets on the thinner side as to make it easy for storage and also if they do not get cold easy they won't get overheated.
4to store your guest sheets,pillow and blanket you can get one of the cube storage bags that you use your vacuum cleaner hose to deflate. this will keep the set fresh, all in one bag and easy to store. put two dryer sheets in the bag with the sheets to keep them smelling washday fresh.