An entirely scientific review.
Cress.
Pros: Such an average herb. You may not be able to do anything exciting with it, but since you always know what to expect, it will never disappoint you.
Cons: Without egg, it's nothing.
Victor Bayon / Flickr: formalfallacy / CC
Catnip.
Pros: It can be used to relieve colds.
Cons: You can eat it, but no one knows how to prepare it. Also it grows near stinging nettles, which is dangerous..
Jennifer Lamb / Flickr: lambj / CC
Stevia.
Pros: You can use it to replace sugar in icing and cakes, which will make you feel very virtuous.
Cons: It's just not as tasty as sugar.
tJj / Flickr: hebam / CC
Patchouli.
Pros: It smells lovely and earthy, and makes gorgeous incense.
Cons: Does anyone know how to cook it?
Mike Cohen / Flickr: mike_c / CC