The classic-loving team over at Joystick Division has cranked out a list of "five things we learned from Deus Ex", or as it might have been better described, "how Ion Storm crafted one of the finest CRPGs in video game history". It's no coincidence that a strong narrative and an overdose of player choice is present in almost every memorable RPG:
4.) There is much benefit to being a good conversationalist.
For as long as RPGs have existed, the charisma scores of characters have suffered as bloodthirsty younguns pumped the strength and constitution points up, allowing their alter egos to heft bigger swords and sustain more potent blows.
But rarely is the art of conversation as important or as engrossing as in Deus Ex. As JC Denton, you can do anything from convince a junkie to trade you his bombs for your future-heroin to talk to a bartender for an amazing amount of time about the politics of your era and the viability of a capitalist state. Sometimes the dialogue was just as exciting and interactive as the gunplay, and just as high-stakes: there are several available narrative threads in Deus Ex where JC Denton comes perilously close to a sexual harassment suit based on his repeated forays into the ladies' bathroom at his workplace.
Being a skilled gunman or elite hacker is all well and good. But if you can't talk to people properly, you'll be missing a lot in life.