One of the successful brands is Rotkäppchen Sekt. Sekt is a sparkling wine similar to Champagne and very popular in Germany. Another success story is Spee washing powder. The Spee factory was bought back by Henkel from the Treuhand, the agency that privatized the East German enterprises, after the German reunification and Spee cleaning products (with the talking fox as its mascot, see here
and below) are now sold in 36 countries according to the Berliner Morgenpost.
Other successful brands are Florena hand creme and lotion and Vita Cola, which is particularly successful in the Eastern part of Germany, the famous Spreewaldgurken, gherkins from the Spree forest, which were featured in the movie "Good bye Lenin".
More information can be found here