Taxes can be a helpful tool in a lot of ways. You can lower them to attract a certain type of development, or raise them to do the opposite, and you get the reward in reaping in the benefits. At the start of many of my cities, I raise all my taxes to 8%. This usually gives me enough revenue in a couple years for a full educational system and fire/police protection. And sims don't usually complain at 8 or even 9 percent. As long as they feel they're getting what they paid for.