Classic mussels

If I had to choose between oysters and mussels, I'd choose mussels, every time. Though I enjoy oysters, I find them sickening after about half a dozen, whereas I could eat heaps of mussels without a problem in the world! Not keen on the big fat New Zealand greenlip mussels--but love the small Tasmanian Blue ones or the small black Sydney mussel--much tastier, seems to me, than the NZ variety--though perhaps in their place of origin they're much nicer.  The small ones are also closer in taste to the delicious mussels of coastal France and Belgium.
There are so many ways you can cook them too, but my favourite is the classic moules marinière, but playing around with ingredients.
First, fry up some chopped onion in olive oil, add garlic, then add the unopened mussels. Toss. Add splash of white wine, chopped herbs--I like tarragon, thyme, oregano with them--then add some water, pepper and a little salt(if they've come in one of those vacuum-packed bags, add the liquid they come in instead, but do not add salt as it's already salty, being seawater).
Cook for only about 4-5 minutes, then serve. Great on its own, or with a bowl of the cooking liquid as soup on the side,  or fabulous too teamed with plain Basmati rice, with some of the liquid stirred through. 
You can also add tomatoes, chilli, etc, to the basic mix if you want, also cream and brandy--in fact all sorts of things can work with these little beauties!