Deus Ex: Human Revolution - Everything Old Is New Again @ IGN

Everything Old Is New Again is the title of a DX:HR preview at IGN, broken down into different sections.  Here's a bit on "flexible, deep gameplay":

Eavesdropping for hints now plays a larger part in determining the path you take through an area. Solutions are less overt than your typical shooter from what we've seen; you actually need to exercise some investigatory skills if you want to gain the most insight into a given situation. Sometimes simply listening to a conversation between two characters can net you passwords or drop hints about secret areas that you'd otherwise not have known about.

The conversation tree is just as flexible; it's akin to Mass Effect's radial dialogue system, where certain options are more aggressive than others – and depending on your tone, the path of the discourse will change dramatically. Again, if you're flippant and don't read into the other character's subtle body language, you'll end up offending them or missing out on key information completely. Of course, if you push a little harder and press for information, you may just intimidate some key facts out of them, rather than simply getting shut down. It's a risk versus reward system applied to conversations and we love it.

Thanks, Omega!