A new replacement for the Duemilanove called the “Uno” (easier to pronounce, thank you), a new usb-serial adapter (with Arduino USB Vendor ID), the new Arduino Mega 2560, Tinker Toolkit (modular system of sensors and actuators) and more!
From http://arduino.cc/blog/2010/09/24/dinner-is-ready/ –
This board will replace the Duemilanove. We decided to be nice to the non-italians and use a name that was simpler to pronounce and write. Uno means one in italian and this board for us is the basic building block of the Arduino product line. We replaced the aging FTDI chipset with a custom made usb-serial converter built with an Atmel ATmega8U2 this provides lower latency and doesn’t require to install any drivers on mac and linux (on windows all you need is a simple .inf file) more advanced users will be able to reprogram the USB chip to make the board show up as a variety of USB devices (Keyboards, Mice, Joysticks, MIDI etc)