No matter where I am, I like to seek out local varieties and producers. Being a West coast girl, I am very fortunate to have many fantastic options. In Washington, I look for Hama Hamas, Kumamotos, and Olympia oysters. In California, anything from Hog Island Oyster Company is great (but especially the sweetwaters when toted to the beach and eaten while watching the sunset...). The above mentioned kinds are perfect for eating raw. If you're going to cook them, go for a medium sized Pacific oyster of good quality- you don't have to be too specific since you won't be able to taste the subtle nuances through all the bacon you're going to put on top...
Now, on to the technical part:
Fold a towel as shown above, creating a bolster to hold the oyster at a perfect shucking angle while leaving enough towel for you to protect your hand with while holding the shell.
Place the oyster in the towel with the flatter shell on top. You want the hinge exposed and the more curved half to hold all of the liquor inside the shell.
Next, work the very tip of your oyster knife into the hinge, trying not to flake any bits of the shell (these will inevitably end up in the part you want to eat...). Make sure to use an oyster knife. Really. Not a screwdriver. Not a butter knife. And certainly not a regular kitchen knife.
Once you've got the knife into the hinge, twist gently until the shell pops open. You will hear when the seal gives way, kind of like a champagne bottle (any coincidence that champagne goes perfectly with oysters??). As you lift the top shell, you will need to run your knife along the side to cut the adductor muscle, and then the shell will open.
You then need to very gently slide the knife under the other side of the adductor (it looks like a little scallop inside the oyster...by the way, the part you eat of the scallop is actually an oversized adductor muscle). Now the oyster is free of it's shell and you can eat it as is or carry on with a topping and some heat.
You know which path I chose.