Thus came MegaTraveller, or MT. In this setting, the Emperor was assassinated and the Imperium devolved into a massive civil war. Thus there was adventure to be had, sides to be taken, villainous pretenders to the throne to be deposed, and so forth. This lent itself better to adventure, but after a few years (nine or so, I think; I believe MT came out in '85 or '86) the setting just wasn't working anymore. I wouldn't know for sure, as I didn't play it back then.
In any case, the result of MT's progression was Traveller: The New Era, or TNE. TNE supposes that a super computer virus, a sort of hardware-software virus which can be transmitted through software and reburn chips, was released as a weapon at the end of the Civil War. This weapon all but destroyed Imperial interstellar society; any machine bigger than a skateboard was vulnerable to Virus, and some worlds depended on massive, intricate computer systems to keep their populace alive.
TNE is set roughly one hundred years after the Collapse. With the help of the Hiver Federation, a small group of human worlds within the boundaries of the old Imperium is rebuilding a peaceful interstellar society. In the way of this Reformation Coalition are dozens of pocket empires, Guilds of spacefaring trader pirates, Vampire Fleets full of ships taken over by semi-sentient Virii, technologically elevated dictators over whole worlds, and xenophobia and technophobia. Despite the number of challenges present, TNE is an optimistic game. PCs are helping to reclaim society, to rebuild things; they aren't just pawns in a war, or renegades traipsing around the galaxy trying to make a fortune.
The game system is the patented GDW house system, which, though I confess I want very much to like, I can't stand. It is convoluted and dice-and-number heavy; it would probably have been gaming state of the art around 1989, but frankly, at this point my preference is for something that lets my friends and I interact, not roll dozens of dice and look up a half-score of tables before declaring "You hit!". I like the character generation system; it allows you to plot out a PC's life before he or she began adventuring, and give him or her the skills that would have been gained during those prior activities.
Many players have problems swallowing the idea of Virus. I have problems swallowing jump drives; if I can accept jump drives, human cloning, and lasers that retain the ability to pack a punch at kilometer distances, I can deal with an Uber-computer-virus.
Traveller is very much a hard science fiction game, with a game like Star Wars being the other end of the spectrum. Spaceship movement is vector-based and realistic, and spacecraft design is equally realistic; to be honest, in many ways TNE can be a game for engineers. The Fire, Fusion & Steel supplement refers to itself as the Traveller technical architecture; it allows one to design almost any technological item from the ground up. It isn't a supplement for the faint of heart; thankfully there are a couple of different sourcebooks with common equipment in them. Understand that I do like both hard-SF and space-opera genres, so long as the game system in the hard-sf game isn't quite as anal as TNE can be.
Outside of game mechanics, I like Traveller: The New Era very much. The background is strong, the source material is full of goodies and very information-dense, and GDW seems committed to keeping Traveller a high-quality line. My preference would be to move TNE over to a game like Hero or FUDGE, and thereby run an easy, quick game system with TNE's setting.
A list of ideas that I think would improve TNE's base setting, the Reformation Coalition