Blocking DC without blocking any frequencies?
Because you asked for "practical" methods, I'll provide an answer which differs somewhat from the others.

Yes, a capacitor (followed by a resistor) will block the DC component of a signal. And yes, if you want low-frequency rejection you'll need a big capacitor. 

But, and this is a big but, large capacitors by their nature are physically large and have large inductive components. This interferes with high-frequency performance, and I seriously doubt that you'll find a unit which will give you 2 Hz to 10 GHz. About 3 orders of magnitude is a reasonable goal for low price. See here, for instance for a line of RF DC blocks with a good unit reaching from 10 MHz to 40 GHz. If you're willing to spend the bucks, there are specialty manufacturers such as Picosecond Pulse Labs (now part of Tektronix) which provide 7 kHz to 26 GHz. A Google on DC block will provide other possibilities.