I'm not an expert, far from it, but I have worked in restaurants and have picked up a few tricks, that I'd like to share.
Most people know that the curly and flat varieties taste the same. Up until recently, only flat leaf parsley was used in Bulgaria. In England, it seems that the curly type is a lot more popular. I tend to get the cheaper of the two for cooking and the curly one for decoration.
The main thing is when cooking is that the curly variety has a more robust cell structure, so it can readily be chopped. The flat leaf parsley should never be chopped, as it goes soggy, it should be finely cut or snipped with sharp scissors.
Another thing about parsley, it tends to go very bland when it's dried, so it's better to buy a larger amount, chop or cut and freeze in a box, ready for use. Don't bother with ice cube trays and water, it's a hasle and would probably need some defrosting before it can be added to the food.
I never liked this as a child and used to pick it out of my food. It's still not a favourite, but I do use it, as Lundulph likes it a lot.
This herb should be cut with a knife or scissors, no chopping. It's good dried too.
I haven't seen this in the supermarket, but it is available in gardening shops. It's a rather invasive perennial herb, like mints, so should be managed in the same way. It has quite a strong flavour, so might not be to everyone's taste. It is good for chopping, freezing and drying.
This is called Indian parsley in Bulgaria, it looks a bit like flat leaf parsley, but feels a lot more tender, so should be cut, not chopped. Good for freezing. I haven't tried dried leaves. Not one of my favourites, but is very nice in curries and spanatchnik. Another one of Lundulph's favourites.
This is the herb that defines Bulgarian cuisine, I think. It comes in two varieties - Summer, which is an annual and Winter, which is a perennial. Generally Summer savory is used, as it has a more delicate flavour. I don't see why it can't be used fresh.
In Bulgarian cooking, spearmint is used. I'm not sure what type is sold in the supermarkets in England, but it's close enough. The smaller leaves are nice as decorations on desserts. It can be chopped and steeped for tea or used in Summer salads together with dill.
This herb is used as decoration on desserts in Sweden, I think it's nicer than mint, which has coarser leaves. I haven't had any success with drying it or making tea from it though, fresh or dry.
In Bulgaria, thyme is used in herbal teas. I think it's very nice in my ratatouille. I think it's a very nice tasting herb. Choppable, freezable and dryable.