I'd say anything within a millimeter or two is pretty good. A centimeter is a big amount. Interestingly, Rolf Prima measures the amount out of true and out of round of their wheels and reports it on their QA sheet that they send with the wheels. From the QA sheet that came with my wheelset, they claim the following, which I have difficulty verifying. I thnk they're a bit obsessive.

Front wheel out of true: 0.2 mm
Front wheel out of round: 0.4 mm
Rear wheel out of true: 0.1 mm
Rear wheel out of round: 0.2 mm