Numeric conversion tools have suffered somewhat from the way Google now allows conversions for just about anything to be made directly in it's search bar.
Still, it's useful sometimes to have a tool that can convert to different units on your desktop, especially if you don't have access to the net on the move. MConvert is one of those and converts just about anything including currency, metric and imperial and more. The tool is divided into several different areas namely Acceleration, Angle, Area, Base, Consumption, Currency, Data, Density, Energy, Energy/Mass, Force, Length, Mass, Permeability, Power, Pressure, Radioactivity, Temperature, Time, Torque, Velocity, Viscosity, Volume.
In the case of currencies, MConvert is updated daily to that it uses the latest exchange rates. There's also a button which takes you directly to the IMF's official rates if you need precise up to the minute data. It supports several conversions at once and you can export the results of all conversion to an Excel sheet. The interface is simple and easy to use with a drop down menu allowing you to select the type of conversion you want to make.
If you've ever found yourself at a loss about how to convert something, MConvert will cover virtually every conceivable situation.