Everyone loves a killer feature: that must-have capability or technology that prompts you to plunk down your hard-earned cash in an effort to upgrade your computing experience.

In the case of Windows, there have been precious few versions that included a truly killer feature. Windows 3.1 was a killer version because it allowed PCs to finally break (or at least reduce the impact of) the dreaded 640K barrier. Windows NT was a killer version (at least for power users) because it introduced the concepts of client/server security and true, hardware-based memory protection to the environment.

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