21" CRT, both at home and work.
My first computer (IBM PS/2 model 50) had a 12" monitor and a 20mb hard drive (don't forget that optional math coprocessor too!). AutoCAD ran like a dream on it (made me tired from waiting), and the dot matrix printer was great for printing out 40 page term papers until it jammed around page 39.
Computers have come a long way in the last 20 years (even 5 years). Stepping up to a 17" CRT was great back in 1996, and now I wouldn't want to live with anything smaller than a 19".
With the introduction of LCD displays, you can pick up a fairly cheap used 19-21" CRT at your local mom 'n pop computer store. While the footprint is large, it's the screen that's ultimately used
