Before I go on, remember that it is completely, 100% okay for these items to be a color other than white. I just find that it is nice for these items to be white because you are able to bleach white. I also find it easier to just buy a basic white item instead of debating what color, and what shade of the color, to buy. So, to keep it simple, just get these items in white.
Bath linens are my one must, must be bleachable white items. Once again, it is okay to buy these in a color, but I would strongly suggest to buy these items in white, especially the bath linens.
Rules for white bath linens:
-At the very least I would purchase one "body" towel and a few white washcloths.
-Buy the softest towels you can afford. If you can only spend more on either the towel or the washcloths, spend it on the towel.
Other items that I would suggest purchasing in a basic white color, for the purpose of keeping it simple, are pillowcases and a white down (or down-alternative) comforter. Since this is most of the bedding, it would be convenient to stick with white sheets so you can wash everything together. Adding a colorful, patterned throw to the end of the bed would add interest so you don't see just white. That being said, I would easily change my mind and buy non-white bedding. But buying basic, white bedding simply keeps it simple and classic. Classic items also cause you to spend less money in the long run because the item is less likely to go out of style or not fit with the decor of the rest of your home.
So, tell me in the comments, are brown linens better because they hide dirt, then I don't have to do laundry?