Consider the iPod: it's a 2.5" hard drive, strapped to a battery and a LCD, that plays MP3 files. Dozens of other taiwanese manufacturers make products exactly like this, but Apple is the only company making a fortune at it, and inspiring fanatical product loyalty. Why? It has the most usable interface.
The mechanical things (coding patterns) are actually quite easy. It's the soft GUI stuff that is difficult, and that's ultimately what makes your product sexy, desirable-- and a success. We may think coding patterns are sexy, but they're invisible to users.
* via HMK's very cool blog