Ayumie Horie makes the most comfortable cups I have ever held. Highly recommended for comfort and smile factor. Her work can be found at www.ayumihorie.com.
Brooke Noble also makes whimsical cups. She usually works with birds, owls, houses and women with umbrellas. Her tumblers fit perfectly in your hand. Recommended use: beer. She doesn't have a website yet, but can be found at www.theclaystudio.org