A strange thing is happening in RPGs: science fiction is popular again. While there have always been science fiction RPGs, they've always been a distant second (or more often, a distant third) to fantasy and even horror RPGs.
Right now though we have three major scifi RPGs in print: Star Wars: Saga Edition, Warhammer 40k, and Traveller. There are also a host of smaller RPGs, including Serenity, Battlestar Galactica, Paranoia XP, Alpha Omega, the Slipstream pulp scifi setting for Savage Worlds and newcomer Thousand Suns.
There are a lot of games to choose from, and from what I can see in blogs and forums, people are choosing them. While I'm sure the fantasy genre is in no danger of losing its #1 slot, science fiction seems to have surged to a strong #2, and I think we can thank D&D for this. Love it or hate it, Dungeons & Dragons 4th Edition is a big change from what came before, and if you're going to make that big of a change mechanically, why not mix things up thematically as well and try a science fiction game? The fact that possible successors to 3E -- like Pathfinder and Hackmaster -- aren't releasing until Summer 2009 only sweetens the pot.
It's what my group did, jumping from D&D 3.5 Edition to Star Wars: Saga Edition, and anecdotally, it seems there are a good number of folks doing the same. It's a grand opportunity to try something new, and I think it's a good part of what makes this a golden age. Sure, you could always play a scifi game ... if you could get the players. But now, you may actually be able to get the players!
It's more than that though: the games themselves are impressive. I can't speak to Traveller, as I haven't picked it up yet, but both the Star Wars and Warhammer 40K games have excellent production values and have solid rules that play to their subgenre tropes. I can't speak to Traveller as I don't have a copy, but the Battlestar Galactica and Serenity RPG's shared Cortex system is a great one for telling character-intensive stories.
Then there's the shear quantify of new material. Wizards of the Coast is releasing new Star Wars campaign and rule books every other month, while Mongoose has been putting out updated versions of old-favorite Traveller supplements, as well as new ones like the Traveller-powered Universe of Babylon 5 sourcebook. They're doing the same with Paranoia. The imperial SF RPG Thousand Suns has already seen one supplement released, and several more are in the pipeline.
You can find even more options by venturing into the universe of PDFs. RPGNow lists 2,200 science fiction-themed PDFs, which is second only to fantasy (5,900 PDFs)! They're you'll find RPG Objects' popular post-apocolyptic Darwin's World and scifi-themed Blood and Space ruleset. Adament Entertainment's released a number of excellent Stardock generic scifi supplements as well as their own d20 (and now Savage Worlds) powered MARS planetary romance game. There are also dozens (if not hundreds) of starship maps, printable maps, and 3D paper models.
I expect it will be getting even better soon: ProFantasy is working on an update of their Cosmographer Pro program and the teasers look fantastic. Fantasy Flight Games is releasing their Rogue Trader core rulebook for Warhammer 40K in the fall and with the positive buzz surrounding the new Star Trek movie, one can only hope that a new RPG based on that venerable franchise might be in the offing as well.
Is this the Golden Age of Science Fiction RPGs? We've certainly had other time periods when scifi RPGs have been popular, but I don't think we've ever had everything (a goodly number number of quality games, a major disruption in the hobby that encourages people to try them) line up quite as well as now. If it's not the Golden Age, then it's certainly a Golden Age; and no matter how you spin it, it's a great time to be a science fiction gamer.