It's no secret that JJ Abrams' is a big fan of the warrior race known as the Klingons. He wanted to use them in a major subplot in the first of his Star Trek films, but had to cut it out. The Klingons have gone through many different forms since their creation in the 1960s, from extremely tanned humans to ridge-headed aliens, so it'd be interesting to see what Abrams would do with them in his own rebooted universe. A new rumor from the reasonably reliable Trekbrasilis notes a source who says the Klingons will indeed be the villains in the Star Trek sequel, set to start shooting next winter.
Another part of the rumor says that there'll be no time travel used in the film, but all of this should be taken with a grain of salt at this point. The Klingons started as a sort of allegory for the Russians, but in later incarnations became noble and fierce warriors who eventually became (mostly) allies of Starfleet. The sudden change in appearance and demeanor, established with Star Trek: The Motion Picture, has been the source of a lot of humor when characters bring it up. I seem to recall Lt. Worf bristling at trying to explain what the heck was going on with earlier versions of his own race. It was later explained completely in an episode of Star Trek: Enterprise.
I really want to see what Abrams' will do with the robotic hive mind that is The Borg, but they're probably the most popular Trek villains and won't be around for awhile. So we'll see how this shakes out, but considering the secretive nature of most Abrams productions, it probably won't be any time soon.
