Any standard op-amp will require calibration of some kind. They all have some offset, temperature drift, and gain skewing. You can avoid that with a "precision" op-amp, but they cost more. Offset is a concern in measuring applications because you amplify the offset by the gain. So for example if you are using a gain of 20 and op-amp offset is 15mV, your offset on the output side would be 300mv which 10% of the ADC count for a reference zero to 3 Volts.
Take a look at the parametric search on TI's web site. They have some real nice precision op-amps. Also, Microchip and Linear Technology have some good precision op-amps. Just narrow the offset parameter in the parametric search on those manufacturer web sites and you'll see them right away. They're actually kind of common since they're often used where high accuracy is required.
A suggestion would be the Microchip MCP6V26.