In the search for species occurence data I stumbled on the Lifemapper project (http://lifemapper.org/). For creating biological models they posess a very comprehensive database. Unfortunately it does not seem to be possible to download everything in one time. Instead you can search and download one species at a time (as far I can see). I'm not looking forward spending days download all species one by one. Anyone has an idea what would be the most efficient way to download all the data...?
according to this Lifemapper page:
Lifemapper gets its occurrence data from the Global Biodiversity Information Facility (GBIF).
In that case, you'd be better off getting the data directly from GBIF, which currently has 458,543,199 georeferenced species occurrence records, and tools for bulk downloading data.