Things to make life easier - white pages & yellow pages

Bankenrechner - wo bekomme ich die besten Zinsen für mein Geld (by Arbeiterkammer)
Currency Converter - by OANDA
Oxford Online Collocation Dictionary - Information und Hilfe mit der Steuer

file sender tool - by ACOnet (Austrian Academic Computer Network)

Mineralogy Database - by David Barthelmy - The Mineral Database, great with localities, ...
Athena OpticMin search - by Pierre Perroud (Geneva, Switzerland)

AGU online reference shelf - handbooks of physical constants (solid earth and planetary geophysicists)

    Baunebenkosten Rechner
eFunda - the ultimate online reference for engineers
Fundamental Physical Constants
Gemstone Information - Quality, value, treatment, imitations
Glossary of Oilfields - Schlumberger
RRUFF database for Raman spectra, X-ray diffraction and chemistry data of minerals
World of Physics Encyclopedia - by Eric Weisstein, Wolfram Research

    Greek-English-Greek dictionary
LEO - great dictionaries
LINGUEE - dictonaries of many languages and translations in many combinations
LOGOS online dictionary
Fischer Weltalmanach - great dictionaries - more than 200!! online-dictionaries