Harvesting herbs

In the summer I picked up a lemon balm plant at the end of someones driveway. I planted it in the garden and it grew like crazy! I really love the smell of lemon, and when you rub the leaves it releases an amazing aroma of citrus. I Googled it and found out a bunch of cool stuff about this particular plant. It is related to the mint family, a calming herb and you can dry it and use it in tea. So I thought I would try to dry some and see how it does. I also read that you can make pesto with it too! What herbs do you harvest?