Well, apparently while The Shower Diva says bachelorette gifts are optional, they do have some recommendations
http://theshowerdiva.com/divaapproved/giftideas-bachelorette.html
Granted, some aren't on the 'approved' list - but we don't care

I recommend the Happy Kit, the Scented Wipes (if appropriate, after you read the whole description), the lingerie
bag (not lingerie!), or, on a more serious note - the personalize M&Ms. By the way, ignore anything to do with Bachelorette etiquette. These tacky people BETTER not be expecting you guests to be splitting the costs!
http://www.catalogs.com/info/weddings-invitations/bachelorette-party-gift-ideas.html Ignoring their (yawn) boring suggestion of sexy lingerie

, this site also lists romantic cds, perfume/body lotion, candles, or gourmet chocolates.
This
http://www.bachelorettepartygifts.com/bachelorette_party_gifts.html site has some interesting suggestions, too, including glow-in-the-dark bubble bath(!) or a "sexy devil" t-shirt; plenty more, too. In addition, especially if you can claim innocent naivety

and, as I did at first, think that 'gifts' meant gifts for the guests - you could get a dozen or a couple of dozen bottles of bubbles! Make generic white labels "Bachelorette Party May 1, 2010" and hand them out as favors

I'm a riot. I kill myself sometimes, I really do.