Don't forget that we can also have high-impedance analog meters, again used regularly in the past in radio/electronics work in the form of the VTVM (Vacuum Tube Volt Meter), or the more modern version with an FET (Field Effect Transistor) input.

Scott,
You'd probably appreciate an old lab-type DVM I have here. Built by the British Solartron company in the early 1970s, it's in a 19" rack cabinet which weighs a ton, and has inch-high Nixie tubes for the readout. Input impedance on the lowest range is over 2000 megohms, and it has built-in calibrators, 50Hz filters, variable-rate or one-shot sampling, maximum/minimum hold etc. I got it for just a few pounds, but it must have cost a fortune when new! [Linked Image]