Comment by jwr

Yes, that series is really good. The calcs I use most often:

* HP-25 (yes, a nearly 50-year old calculator, but you can hold it in one hand and it does most things I need very well)

* HP-11C or 15C (doesn't matter which, I don't use the extra features of the 15C)

* HP-12C

* HP-50G (very useful for unit conversions)