You guys know that these are available as Windows programs too, right? They have them for the iPhone, iPod, Palm, DOS, etc, too.
I have an HP-41CX Calculator (among others in my collection, even a 91 and 97), that I use.
There is an equivalent HP-41CV/CX for download on the web (Google V41 calculator or
http://www.hp41.org/Emulation.cfm). Looks and works just my real one. The only problem it has that I know of is a problem loading the font. You just okay the message after you have fixed the font once and it runs fine. Use it all of the time.
Some other HP Calculator Emulators (16C, 48, 49, 50) are here:
http://www.hpcalc.org/hp49/pc/emulators/Edit****
Sorry, they made an emulator for the 15C not the 16C that I mentioned above.
Ross