I was cooking pasta Alfredo the other night and I grabbed the big container of garlic powder I keep by the stove. Somehow, I got the two pour spouts confused. Rather than adding a teaspoon or so of garlic powder, I wound up with two or three tablespoons in my sauce. I've been looking for a spice dispenser capable of preventing a repeat performance, and I think the SpiceShot Spice Dispenser fits the bill.
With SpiceShot by Chef'n, all you have to do is pick it up and click a button. A quarter of a teaspoon will fall right into your bowl. If you need a full teaspoon, just click the button four times. The SpiceShot is limited to ground spices--whole leaves and large seeds won't work with the device. You can operate it one handed, which is always a good thing when you're trying to get dinner on the table.
You can pick up your own SpiceShot for $7.95, and they come in five colors if you're planning to outfit your entire spice rack. It is difficult to switch out spices in the dispenser though--when you fill the SpiceShot, it's for the long haul, so I wouldn't recommend it for any spice you don't use regularly.