What elements push a game beyond mere goodness and into greatness?

To this author, PC games are best when they deliver a transcendent gaming experience that is possible only with the aid of a personal computer: They don't simulate board or card games, reproduce real-world sports, or try to approximate movies. They are an art form unto themselves.

I surveyed dozens of PC game developers, asking them to share their picks for the ten greatest PC titles of all time. In addition to weighing their opinions, I took into account factors such as influence, innovation, design, and replay value.

To be considered, a game must have achieved most of its prominence on a PC platform. (This explains why Tetris, for example, didn't make the cut: It was clearly the Nintendo Game Boy's killer app). I defined a "PC" as any consumer computer that has a keyboard the user can program with arbitrary code--not just a PC of the IBM variety.

If you're into PC games, check out "15 Reasons PC Gaming Beats All," too. And if you want to stay current with the latest games, tune into PC World's ace gaming blog, Game On.

Without further ado, here are our ten greatest PC games of all time, counting down from Number 10, Trade Wars 2002.