by , 10:50 AM EDT, April 15th, 2008

There's one main thing at the heart of Apple's success, according to Forbes magazine's Brian Caulfield, and if you think it's the company's great industrial design, there should a loud buzzer sound going off near you. Instead, it's all about the software that runs in that hardware.

Mr. Caulfield's observations, which we found to be poignant, came in a piece and slideshow looking at what Forbes thinks are the seven greatest innovations in Apple's history.

"Everywhere you turn this year, Apple's machines are on the march," wrote Mr. caulfield. "The common denominator? Software. While great industrial design always attracts gawkers, it's software that makes Apple's proliferating array of machines so comfortable to use on a long-term basis."

"Apple's best products," he wrote, "mix the curb appeal of a Lamborghini with easy-to-drive friendliness of a Honda Accord."

Mr. Caulfield also noted Apple's ability to make "the whole widget" -- i.e. controlling both the software and the hardware -- is an important element to why the company's software works so well. While the rest of the computing industry flocked to Microsoft's anyone-can-license business model starting in the 1980s, Apple's adherence to the earlier model of making that whole widget makes it possible for the company's products to work more smoothly.

That observation is particularly timely, especially coming from a mainstream source like Forbes, in light of the controversy over Psystar's Open Computer, which the company is marketing as a cheap alternative to Apple's hardware if you want to run Mac OS X. What does "Mac" mean if the concept includes non Apple hardware?

That's a question for another time, but it's worth considering as you check out Forbes' slideshow of the seven greatest innovations in Apple's history. Those seven are OS X (not listed as Mac OS X, we might add), iLife, iTunes, the original Mac OS (check out the picture of Steve Jobs in a bow tie from the 1980s), John Sculley's Newton, iPhone, and iPod.