I think it's super important to have bathroom supplies on hand so guests can help themselves to items they didn't think to pack. Enter the "Guest Jar". I pick up 2 gallon lidded glass canisters at Walmart ($9.97), and fill them with samples (including the stuff I bring home from hotel stays, that I never end up using). Then I add labels which read "For Our Guests", and tuck them under the guest sinks. They're pretty popular with our guests!
I'm also a believer in robes; don't you always miss yours when you don't bring it with you? So I picked up some extra soft white robes, and had them embroidered. They each say "Guest", but one is embroidered in blue and one is in pink. They hang in the guest room closets, but always end up in the bathrooms (imagine that).
Each guest closet also holds extra pillows and blankets, a fan, and a luggage rack.
