For me, total indulgence, would be a tie between Lindt Milk Chocolate and Ferrero Rocher (including Raffaello). But for sneaky everyday chocolate, anything Dairy Milk.
My favourite chocolate is by Hotel Chocolat; they do a 100% using cocoa beans from their Boucan estate in St. Lucia. If you are talking about confectionary chocolate, the Dairy Milk Fruit & Nut is my favourite, closely followed by KitKats.