By far the most useful herb for me is parsley.
I use it on and in many of the dishes I prepare and especially if I am putting it on Recipe Yum, as that small piece of parsley just gives the photo a slightly better look.
I also really like parsley and often chop up a lot with chopped tomatoes -parsley goes with just about everything, and so I have it growing in several places.
I also use garlic chives which I have had growing for years however now it is start to not re-generate as it used to, so will probably re plant.
I also have coriander growing almost wild everywhere. I use coriander in quite a few dishes also. This keeps coming up year after year and I have many seeds I have taken from them which I also plant all the time.
Most other herbs I do not use a lot of so just buy as I need them.
I use so many on a regular basis,and I grow all my own!!Curly Parsley,Italian Parsley,Chives,Garlic Chives.Lemon Basil(Yummy for Fish!!) normal sweet basil,tarragon,Mint,Rosemary,Culantro(Mexican or Perennial Corianer),Lemon Myrtle,Bay Leaves,and that is for starters!! I also have somehow managed to grow my own Lavender here in the tropics which is very unusual!!! Something which grows all through my yard is Arthritis Heb,though I have not found that it works for me!! Fresh IS Best!!!
We don't grow anything since we are living in a house that is not our own on a temporary basis. Of all the herbs, I think I use oregano most often. I also use parsley, basil, dill and marjoram. I would love to have a herb garden when we get a place of our own.
I use Italian parsley in my cooking, but I have to buy mine. It keeps longer if it's wrapped in damp paper towels & put in a sandwich bag in the veggie drawer. If i have some left over when I'm going on holidays, I'll chop it up, & put it into ice-cream trays, & freeze it, then put them into snack packs or sandwich bags, depending on how many I have.