The best calculator I ever had (other than the HP-41CV in the early 1980s, naturally) was one built into my first PC keyboard (circa 1991). I could never lose it, and it had a special key that fed the result of the calculation to the current app. Eventually, though, it stopped working.
I like having a biggish-size desk calculator for quick calculations. I prefer it over the calculator function built into Windows, or using my Palm TX's calculator For a while I used a printing desktop calculator from Texas Instruments, but it was a awful: its rubber keys often failed to register my keystrokes.
Last week at Wal-mart I saw a nifty looking calculator for $30 and took it home. The Canon DK1000i mimics the numeric keypad of computer keyboards (see image here). It works three ways:
1. Cal Mode: As a desk calculator.
2. PC Mode: As a numeric keypad for notebook computers (via the built-in USB cable).
3. Bonus PC Mode: As a two-button trackball and cursor pad (also via USB). I found the trackball too fast for my liking.
The PC/Cal button toggles between Calculator mode and PC mode. The Canon has three power sources:
1. Standard CR2032 lithium battery.
2. Solar cell.
3. USB cable.
In addition to the large 5/8" LCD number display, it has these features that I like a lot:
1. V-e-r-y nice buttons that feel like a regular keyboard.
2. The USB cable is retractable; a spring reels it back inside the body of the calculator.
3. It has the very useful Send button, which sends the result of calculations to the current application -- just like my old keyboard did.
Functions are limited to +, -, /, *, %, and tax, along with rounding and memory; it has a backspace key for correcting entries. The overall size is 4.5x7", which is large enough to not get lost on my messy desk!
Truly remarkable for $30. Thanks to whoever at Canon thought up this product!