The LM324 family of devices has a quad op-amp with a true differential input with a true differential input. They have some significant advantages over standard operational amplifiers for single-supply applications.
The quad amplifier can operate at supplies as low as 3.0 volts or as high as 32 volts with a static current one-fifth that of the MC1741. The common-mode input range includes a negative power supply, thus eliminating the need for external bias elements in many applications.