An Arduino is one of the cheapest ways to built your own electronics prototypes and projects, but the Arduino Uno isn't exactly the most powerful device on the planet. If you're looking for something with a little more punch, the newly released Arduino Due should do the trick.
The Arduino Due has a 32-bit ARM core (the Uno is 8-bit), an 84Mhz CPU clock, 96KB of SRAM and more USB ports than the Uno. In short, it's a much more powerful microcontroller that can handle a lot more than previous versions. A new set of libraries has been started up for the Due, as well as a dedicated forum for help getting started. The Arduino Due is backwards compatible with all your current Arduino sketches, but the added power should be enough to supercharge any upcoming projects you're working on.