I grow mint because I like iced tea during the summer. Steep the mint with the tea bags and you have a nice summery drink. Mint is great to have on hand for when you want a mojito.
I also grow chives, basil, parsley, oregano, dill, sage, cilantro & rosemary. I also planted some catnip. Our cats (and some neighborhood cats) hang out in the garden which keep away birds, squirrels etc...
Consider growing radishes too. Radishes have a fast grow cycle and you can get a new crop every 30 days. They don't take up that much more room than typical herbs.