Sweet wine with sweets? Not necessarily when it comes to pure chocolate. If what you have in mind is chocolate cake or other chocolate-based desserts, for instance, you're better off sticking with dessert wines. My suggestions are for chocolate by itself--good-quality pieces or truffles. There's no need to break the bank, but remember that cheap chocolate is mostly fat and sugar. What we're really after is the stuff that has a nice shine, a good cocoa butter content, and is smooth as silk on the tongue. Wine doesn't only favor dark chocolate, mind you. My pairing ideas below include milk chocolate as well.
I have found that a good rule of thumb is to match dark chocolate with dark wines, ones that are dark in color, higher in alcohol, intense in flavor, and robust in general. This wouldn't really include Pinot Noir, for example, but rather a Zinfandel or a big Napa Cabernet Sauvignon. Even better, a ruby Port. Ruby Port delivers all those attributes, plus the right sweetness for chocolate and a vibrant berry character. This is why the two are a classic match. Don't like Port? Try the Zin or Cab, or an Australian Shiraz. If tawny Port is more your bag, reach for chocolate with nuts in it as it will really bring out the irresistible nuttiness of the tawny.
If we consider the same guideline, lighter chocolate would logically go well with lighter wines. This includes sweeter wines made from white grapes, like a French Sauternes. Wine writer Natalie McLean suggests trying that with chocolate that has some cream in it, like ganache-filled truffles. For milk chocolate lovers, you could try a Canadian Ice Wine. (It's called ice wine because the grapes are harvested while still frozen on the vine, which means the water inside the grapes is frozen solid and all that pours out when the grapes are crushed is a concentrated juice of sugars and acids.) If you'd rather enjoy a red wine with milk chocolate, you could reach for that Pinot Noir or a lighter-bodied Merlot. Just remember that because milk chocolate is sweeter than dark, the dry wine might end up tasting a little more bitter than it actually is. But hey, it's all about what tastes good to you. Not all palates are created equal, so what might be a heavenly match for some might be a train wreck for others. Experimentation is the name of the game!(I personally really enjoy Dove chocolates. They're affordable and always satisfying, especially the red foil-wrapped dark chocolate. If you happen to agree, check out their site for their approach to pairing wine with their products.)