in your cart, create a new taxable column. For taxable items, set the value of this column to 1, none taxable items, use 0.
for the tax and shipping rules, Use the "Based on items With A Specific Column Value" trigger:
If the Total Number Of items where the Column [Taxable] has a value of  is [>] a
value of 
This used so the rule will only apply if a taxable item is in the cart.
For the calculation, use "Based On Items With A Specific value":
Total of [TotalPrice] where [Taxable] has a value of  [times] [0.05]
For a 5% tax
Total of [Quantity] where [Taxable] has a value of  [times] 
for a 2 dollar per item shipping