Gates Carbon Belt Drive on a Dahon Uno Mu. This is amazing... It no doubt costs as much as the bike itself but it sure is awesome! No lube, no dirt, no noise... Combine it with with an SRAM Automatix hub with coaster brake and I'll swoon. (This one is combined with an old F Duomatik hub!)
ThinBike by Schindelhauer. Isn't this just perfect? "A full-size bicycle with inventive and elegant solutions for inner-city traffic, like an integrated taillight or a bell built into the brake lever" Includes a carbon belt driven 2-speed internal hub. The pedals fold, and the handlebars twist for a very narrow profile!