I just bought a second hand scientific calculator, I bought it because it displays 7 lines of calculations, I'm still wondering if I got ripped off but it was somewhat cheaper than comparable calculators on auction, but even if I didn't get ripped off... what the fuck. It has a 3 colour screen, 64k storage, you can buy a smartphone with a high resolution full colour screen and a half a gig of ram and a dual core, storage, connectivity, the list goes on, for a similar price... the only difference is the calculator has some buttons that are much better suited for calculating than a touch screen + some software.

I think someone who made a bluetooth keypad with calculator buttons on it + an android calculator app to use it with would be a millionaire.

What calculator do you guys use/recommend?