1. Need to be able to specify sales tax by category and disable it from certain products. In the State of Florida sales tax is charged on tangible goods, but not on services. I am sure there are different model in other states.
2. Need to be able to specify sales tax to not be charged on items shipping out of state. Most states do not require vendors to collect sales tax on items shipping out of state.
3. Need to be able to specify varying sales tax for in county purchases, vs. out of county purchases. Some counties have optional "local" sales tax add-ons. The sales tax code allows for up to 1% of local add-on taxes. This must be collected for any item shipping within the county where the business is physically located.