I am a firm believer on the importance of a good night's sleep, which is to says there is little I will not do to achieve that. (Imagine this: my husband frequently travels for business and stays at Four Seasons and Ritz properties. When he comes home, I get the download on the hotel stay: food, bed/linens, service, room, toiletries, etc. More often than not he'll say the sleep experience was good, but never better than our bed.)
I agree with 1chicretreat: White, white, white for sheets, shams and duvet covers. I am gaga over fine linens myself, which started in my early 20s when I dated the owner of Helmy's House of Fine Linens in Beverly Hills. He totally spoiled me and ever since I buy nothing but French or Italian (Sferra, Yves delorme, Frette, Anichini, etc.) Egyptian cotton linens. This goes for the vacation rental, too, where I strive for a five-star experience. Absolutely, I pay more up front, but they really do last for years and years, get softer with each use, and my housekeeper has been educated to not "cook" them in the dryer. And yes, she always puts the sheets on the bed when they're damp dry.
I realize this is not feasible for the majority of Air hosts. For many, it simply doesn't pencil out financial to spend so much on linens. But I highly recommend taking some of your hosting cash flow and buying a set for your own bed. Meredith has great resources on her blog. If you have a Tuesday Morning near you, they often carry Sferra and other Italian linens at deep discount. I picked up a king set of Tessitura Toscana whisper thin 100% EC sheets for $120 just a couple months ago.
Colorful euros and cotton quilts dress up the bed (and protect the duvet covers from that occasional piece of luggage). Everything down. (I wash my down pillows and comforters all the time.)
Protectors on all the mattresses, pillows and duvets. Double sets of everything, which is a necessity during peak season when we have back-to-back guests all summer long.
Learned my lesson the hard way on colored vs white towels in my VR. Three colored RL hand towels ruined in two months by acne creams and/or silicone based lubricants. Ugh. TMI?