Why use the default icons for your computer when there are so many good artists producing free icons? Here's a few links to some of the best tiki icons on the web.
The Iconfactory currently has three sets of icons for both Macs and PCs, including one inspired by the art of Derek Yaniger, an up-and-coming artist who has designed many tiki event posters in the last year.
Tiki Cup icons by Don D'Abo are excellent reproductions of famous souvenir tiki mugs for Mac OS X and Linux.
Artist Pinboy has three sets of tiki hard drive and folder icons for OS X.