Sounds like there are a lot of people here who should be heading over to this week's contest--your best seafood pasta!

Per ChefDaddy's comment, his method is almost exactly what I would do. Possibly give it a Spanish twist by substituting toasted fideo noodles for the linguini and swap the hot pepper for some piment d'esplette or pimenton ahumado. If possible cook them in an earthenware vessel that you can cover with a lid until they are all singing. Actually I do like a garlicky butter as well.
And as others have noted make sure you have good quality mussels (I don't think much of NZ Greenlips) as they are a very sustainable and inexpensive seafood.

When I do mussels, I keep it simple: After cleaning them and pulling their beards, I toss them in saucepan, pour in a glass of white wine, some minced garlic and some chopped parsley. Put the top on, turn the stove on and steam them open, giving the pan a good shake every now and again.

That's it. If the mussels are good one, the butter seems superfluous to me.

About cavatelli, mussels, small tomatoes, basil, garlic, white wine and extra-vigin olive oil.

The pasta dish sounds great, but I'm thinking that AmyKlegs wants a purer lesson in how to cook mussels. How about Amanda's recipe from The Cook and the Gardener:
http://www.epicurious.com/recipes/food/views/Mussels-with-Garlic-and-Fines-Herbes-101374

Not to sway you from your buttery-wine-garlic idea, but the recipe that's shown above http://www.food52.com/recipes/2092_mussels_for_one_or_two?fp2r is out of this world.

Cook some linguini al dente and drain.
Add butter fine chopped shallots and garlic to large hot pan and cook for a minute or two and add white wine and clean clams a little salt and red pepper flakes. Cover and cook until clams open only a few minutes. Taste liquid and adjust as needed. Add pasta and toss, garnish and serve. Simple, light, elegant and good, but is it Italian? I don’t know maybe my pal pierino can way in and shed some light. Either way I love it!

Oh I love that! I scrub my mussles and then (not much measuring) sweat a lot of garlic in a lot of butter, add a good splash of white wine and I like to add a dash of tamari. Finish with chopped Italian parsley and serve with a baguette that you rip apart with your hands as you go - that's it!!!

Some general advice in addition to takeanonion's: before you cook the mussels, sort through them, cleaning them up if necessary. Put aside any that are gaping, and toss any that are cracked. Then go back to the gapers, and toss any that haven't clammed up. Bon appetit.

http://www.epicurious.com/recipes/food/views/Mussels-a-la-Mariniere-232973

try this - mussels are very forgiving - just remember don't eat if they don't open after cooking