Here is a robotic arm with a modular design that helps you get started with Arduino and robotics. It has an open source controller and lets you upgrade it for your projects. The robot arm has a control panel that lets you control it right out of the box. Its servos let it pick up 50-gram objects. The Gripper has adjustable angle finger tips.
The Snapper Robotic Arm is powered by a Geekduino. It sensor shield lets you change sensors easily. More information is available here.