If you've been looking for some inspiration to get started with (or finish!) your own robotics project - check out the "Mars Rover"-style robot by the people at Beatty Robotics. It's an incredible facsimile of the real robot by NASA, powered by an Arduino Mega board and contains a wide variety of sensors and can be controlled remotely via XBee wireless. The final purpose of the robot is for use by museum visitors - they'll drive it over a simulated Mars landscape to search for infra-red emitting rocks. Sounds like fun, and the following video shows the robot in action:
When building complex projects that will outgrow the normal Arduino-compatible boards, such as running out of program and flash memory space, or you're stacking on Ethernet and microSD shields, or all at once - it's time to upgrade to the Freetronics EtherMega:
Quite simple the EtherMega is the fully-loaded Arduino-compatible board on the market today. Apart from being completely Arduino Mega2560-compatible, it includes full Ethernet interface, a microSD card socket, full USB interface, optional Power-over-Ethernet support and still has a circuit prototyping area with extra I2C interface pins. So if your project is breaking the limits, upgrade to the EtherMega today.