I'll do a post on PC Games in the future if this one garners any interest. It's kinda difficult to focus on DOS only though, as I feel a lot of DOS games have been made redundant by later releases. Off the top of my head, the original XCOM and Heroes of Might & Magic 2-4 are probably the main ones that stand out as never being overthrown by subsequent titles. Then you have titles like Ultima VIII which a lot of people hated, but I thought was pretty amazing at the time.