The last thing I want when I go to a shower is a trinket or a dollar store bath item that will break my skin out. Those type of things are ususally tossed as soon as I get home. For my sisters shower we hit the Bath and Body Works big sale and loaded up on the anti-bac hand soap. Very much appreciated by our guests.
The best favor that I have ever received and seen done at a shower was one that was household goods. It was done for my uncles soon to be wife and when we came in we were greeted at the door and given a slip of paper to write a wish or piece of advice for the couple. As the bride opened her gifts she pulled one slip from a basket, read the wish/advice and that person got the gift. There were enough gifts for everyone. And the gifts? Toliet paper, paper towels, dish soap, dryer sheets, air freshner, Windex, Pledge, etc. Now those are items that we use!!!!