If you want to talk about the most important product, it had to be the Macintosh A.K.A Mac. This let ordinary people use a computer for personal use and not just work. It would let people play games, featured a mouse, let people listen to music and many many things. Without this, Apple would not have everything it has today. The best one that people like the most, statistically speaking, is the the Iphone first introduced in 06 or 08 not sure. It has had the most sales of any Apple product as of today.