It looks like Eidos might be getting a bit creative with Deus Ex 3's title. New trademark applications suggest they'll be going the subtitle route.

Siliconera noticed that Eidos' parent Square Enix has trademarked Deus Ex: Human Revolution in Europe. They've also snatched up Deus Ex Human Revolution and Deus Ex: Human Revolution in North America.

The second game in the series was called Deus Ex: Invisible War rather than Deus Ex 2 so no big shock that the third game would be unnumbered. It's going to be a prequel to the previous two installments, as well, so putting a "3" on the end might've been a bit confusing.