What should be my next LED HP calculator?

[Dave Britten]

I'd vote for a 45. It's (relatively) inexpensive, has lovely keys (you may need to open it and clean the contacts), a fantastic display with wide viewing angle and all 10+2 digits, and is just a great scientific calculator with a well-rounded set of functions. Plus you can drop in a Classic emulator board to "upgrade" it to a 55 or 65 if you so desire:

https://www.hpmuseum.org/forum/thread-9847.html