STMicro's L6470 (a.k.a "dSPIN") is a 3A, 8-45V bipolar stepper motor driver. It has built-in overcurrent detection, undervoltage detection, overtemperature detection, stall detection, a 5-bit ADC, and a switch input that can be used for either user jog control or as a hard stop function. As if that weren't enough, it also features microstepping support (up to 128 microsteps per full step) and PWM drive voltage limiting.
Unlike most stepper motor drivers, the dSPIN is controlled over an SPI link. It has an on-board 16MHz oscillator which allows it to autonomously execute movement commands. That means no more counting steps in your code! It also supports customized acceleration and deceleration profiles to prevent jerky starts and stops. On-board registers track current speed and location.