Kaypro II
I got my Kaypro II from a Boy Scout garage sale. A Boy Scout garage sale where I was one of the Boy Scouts, of course. One of the parents who was involved in the troop had brought it in to sell, and said he was hoping I would end up getting it since he trusted that I would use it well.
The CRT on this thing is excellent for text. I love playing Zork on it. In fact, this is probably the best Zork experience you will find in any machine. Word processing is quite excellent as well, and spreadsheets are not too bad.
Realizing that I could lubricate the keyboard made all of the difference in the world. I'm surprised it took me so long to figure out that it was possible (and necessary), but to be fair I was pretty young when I first used the machine. I didn't even have YouTube available to show me how to care for older machines.