I use the right mouse button every day at work on my Dell PC. At home on my Mac, however, I am not crippled by the one button mouse because I can use keyboard/mouse click combos or click/hold the one button and do what I could do with a two button mouse.
If it were a crippling blow, I would just buy a two-button mouse for my Mac. They work just fine but for me are not necessary. Same goes for the floppy drive. I bought an external one for my first floppy-less Mac. It now sits in a box in the basement. Haven't needed it in over 5 years.