Where can I find a complete and accurate table of CPK colours?
Indeed, this is annoying. Because of this problem, several years ago, one of the Jmol developers and I sat down and worked out a color scheme. It was similar to Accelrys, although we tried to make certain "known colors" match (e.g., rust-like for Fe, golden for Au, etc.)

Certainly, there's been an effort to keep color consistency between Jmol and Avogadro

These colors are open source and available, e.g., through Open Babel

If there are differences between Jmol and Avogadro, I'm sure both the Jmol developers and the Avogadro developers (including myself) would be happy to reconcile them.