Pure dark chocolate is generally the easiest type of chocolate to pair with wine but often nuts and caramel will draw out similar characteristics found in the wine.
Think rich chocolaty Cabernet or Port with dark, a toasty-rich bubbly with chocolate covered nuts, a tawny port if there is caramel involved, white or milk chocolate with late harvest or icewine sweeties...and a spicy Shiraz (or sparkling Shiraz) with chocolates infused with chilis or pepper.