You know those old pancake-flat pillows you keep in the guest room? Well, throw them out because no one -- not even your most exhausted visitors -- will be able to get any sleep on them. Think about it: If the pillows aren't good enough for you to sleep on, why would they suffice for anyone else?
If you plan on trying to lure holiday visitors back to your abode in the future, pick up some nice down pillows (they're great for allergy-prone guests) or fluffy, high-quality synthetic ones. You also can't go wrong with memory foam, though it may be a little pricey (especially if you've been stocking your guest room with pancake pillows to save a buck or two).
Also, remember to wash your pillowcases every few weeks, even if they haven't been used, and put fresh, clean sheets on the bed before your loved ones arrive. Dust particles won't ignore your guest bed, no matter how uncomfortable your pillows may be.