Well, i already own an xbox, however i refuse to support tremulous on the xbox for many reasons (most of them being playability and the closed source-ness).
Going by the Wikipedia page, the idea of tremulous is at least 4 years old. Four years of people enjoying a completely free and open source game that can be played on just about any pc. Cutting to the chase, Xbox is where games go to die. I personally cant think of an xbox game of the same age that i could pick up and love just as much as tremulous (let alone an xbox game for free). On the second note, now that Microsoft has their hands on it, i highly doubt that tremulous will be the same game anymore. Tremulous 1.1 took some time for me to begin enjoying, mostly because it took some time for me to refine my skills, and thus i defined tremulous as the game that rewards time and effort. Microsoft doesn't want to make a game that takes a long time to get good at, too many people will quit within the first month of playing. Most likely, Microsoft will change tremulous enough to make it easy to pick up and play straight away, and im guessing that the new alien class & the new human what-ever-it-is will be the easy class to play and get a million kills. Thats not tremulous.
Xbox is a wonderful machine, but tremulous has no future on a console.
Extremely unorganized paragraph, fueled by rage. Timbo's choice to move to the xbox will now conclude my last post on these forums. Good luck.