CCH is now offering tax products that hook into GP 10 including a hosted solutions that ties to GP 10’s Sales Order Processing module and a sales tax updater for updating the sales tables in GP.
I don’t have any experience with the product but my rule of thumb is less tax is better. If you have to be taxed, more choices for processing tax is better.
CCH Comes to GP
Off-Topic & MiscellaneousGP 10
Archived post from 2007. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.