Some Data Sources...

Official statistics for Austria & EU:
http://www.statistik.at/web_de/services/index.html

InfoChimps - all and everything, rather US-centred, mostly census-data:
http://www.infochimps.com/

BIOLFLOR - Comprehensive database on species traits of plant species (German flora), overwhelmingly extensive:
http://www.ufz.de/biolflor

GBIF - a compendium of  almost all species-distribution databases available:
http://www.gbif.org/

IUCN-Webpage, spatial data for endangered species:
http://www.iucnredlist.org/

EEA, Eionet Central Data Repository. Spatial, environmental, diversity data, etc: