While going through my my PC game shelf I came across some classic PC games that were great games -- but for one reason or another failed to thrive to the present day. I decided to devote an article or three to some of them.
Myth: The Fallen Lords
The Myth series included Myth: The Fallen Lords, Myth II: Soulblighter, and Myth III: The Wolf Age.
Myth and Myth II were made and published by none other than Bungie Studios in 1997 and 1999 respectively. Myth III was created by MumboJumbo, and it held up to the first two games quite well in my opinion (especially in light of the having a very rushed development period). To this day, the Myth series is still one of my favorite RTS games of all time.

The Myth series was one of the first RTS games to take advantage of a 3D engine, terrain physics, weather, and other elements to create a challenging, tactical experience that was quick to learn and play -- but seldom easy to beat. Myth eschewed base-building and resource gathering, plunked you down with an army of different units (archers, footmen, berserkers, and others), and challenged you to win the day with superior tactics. Making use of terrain was especially important -- for example, forcing (or baiting) the enemy through a bottlenecked mountain pass, or forcing them to attack you uphill, giving you the advantage of high ground. Experimenting with different tactics was often half the fun.

Without any bases to build or resources to gather, Myth was also an excellent multi-player game. Matches were quick and easy to set up (even over a modem), and you could easily play half a dozen games in an hour.
Another reason the Myth series really stuck with me was because it incorporated some of the best fantasy fiction I've ever encountered in a video game -- bar none. (Heck, I wish I'd written it!). You can visit Bungie.org to view and read many interesting tidbits about the Myth universe. (Note to Dungeonmasters -- the Bungie.org site is rife with great ideas to use for adventures and other D&D/fantasy-type material for RPG campaigns.)
To this day, the Myth series is dead, but there are still a few sites dedicated to hosting community-made content, mods, and other Myth-related content. (I've included a short list of those sites below.) Given that RTS games are still plenty popular on the PC, I think a Myth revival could and would be a critical and commercial success in the right hands.
Here's hoping that, if nothing else, maybe the Myth series (and other 'dead but good' franchises) can be revived through digital distribution sites like GOG.com.
Read the Myth Wikipedia entry for more info
Read the 'Bungiepedia' entry for more info (Official Bungie Wiki)
Myth community, file and fan sites: