State tax rates and rules vary significantly. Since federal rates are much higher than state rates, you usually think of federal tax planning first. But you should also know a bit about tax rates in your state.
State long-term capital gains rates range widely. California has the highest, at 13.3%; several states have none.*
important For this reason, some people even consider moving to another state if they are likely to have a windfall gain, like selling a lot of stock after an IPO.