I don’t know about everyone else, but I’ve found Google’s calculator feature to be one of the most useful things in the lab (it’s that or an oscilloscope). It’s the first thing I go to when I want to make some little back-of-the-envelope calculation. And it’s always there, no matter what computer I sit at (unlike the ‘scope, which is always getting “borrowed”).
My most-loved features are it’s physical constants and the way it incorporates units automatically.
Now if anyone from google is out there and wants to make my Christmas, add a resistor color coder/decoder
resistance: green brown black gold ?