Yesterday we found out that comedian Patton Oswalt had joined the cast of the Battlestar Galactica prequel series, Caprica. Now comes word that another well-known name to the geek community will be joining the cast as well.

MTV News is reporting that Buffy the Vampire Slayer and Angel star James Marsters has officially joined the cast of the show, which is set to begin it’s first season (after the prequel movie, of course) in January of 2010. Marsters will play a character named Barnabus Greeley, a terrorist who’s having troubles distinguishing whether what he does is right, or horribly wrong.

As those of us who have seen the prequel movie know: Daniel Graystone’s (Eric Stoltz) daughter, Zoe (Alessandra Torresani), was involved in a organization for which she thought was morally correct and turned out to be an actual terrorist group who go to extreme measures to accomplish what they believe to be right.

With these new castings, Caprica is looking better and better every day. The cast has a lot of recognizable faces, but no superstars — which is one of the great things about BSG, and one of the reasons we the fans just can’t wait to get more in 2010.