I used really rich 70% cocoa solids chocolate, which was delicious, along with dark chocolate chips as well! I'm really not a fan of Christmas Pudding (I really hate anything with currants, raisins, and all that jazz) so these are a great alternative, and they'd also make awesome gifts!
The white chocolate "cream" could have been neater, but overall I'm really happy with the outcome of my little muffins, and although they were a little heavy, they tasted great. I really have no idea why I am so bad with cakes...alas, they looked good so I'm pleased. Hooray for Christmas baking!