Chocolate
Now for the main player. Chocolate is sooo good. Fortunately we are the beneficiaries of the recent chocolate revolution (one among so many, thankfully). Once upon a time you could only find Hershey's chocolate at the grocery store, and that stuff is awful for making good chocolates. Now you can get all kinds of high quality products quite easily. Some good quality brands include Lindt and Giradeli, as absolute basic grocery store brands. I know that brands like Callebaut is sold at Whole Foods. I've seen it on their table o' chocolate. If you can find Valrhona brand chocolates you're in good shape, as that is a great quality chocolate. I even recently found out about Cargill's line of high end couverture (chocolate that's suitable for making truffles and candies). It's called Peter's Chocolate and it's pretty good. Whatever you choose, just make sure it's a high quality product. Low quality chocolate simply will not work, plain and simple.

There is one thing to keep in mind when you get your chocolate. You probably want to choose one with a higher percentage of cocoa butter. That means a dark chocolate, bittersweet or semisweet. If the chocolate has a percentage on the package, go for a high percentage, like 65 or 70. The percentage refers to the amount of actual cocoa in the bar, both cocoa solids and cocoa butter. Everything else is sugar and/or milk. While you can use milk chocolate and white chocolate, they don't like to behave as much. Even with some experience, milk and white chocolates are more difficult to manipulate. I recommend starting out with dark chocolate because you'll get good results more easily.