Personally, I was the owner of a HP-48GX. Thus my preference goes to this calculator
Even if the code have to be remade, all the graphics are still usable.
Here is a list of games available on HP-48: http://www.hpcalc.org/hp48/games/arcade/
I’ve begin to port Diamonds (http://www.oocities.org/doug_cannon/), one of my favorite games on the HP-48.
Port is near to be finished and I’m looking for some beta-testers. Anyone interested ?