For a taste of what's coming in the next generation of games, you could do worse than check out this monster download of Half-Life 2, the most anticipated game in history.
Funny enough, the 'game-play' people are lining up for is simply the ability to fiddle around with the terrain and props in each scene. Shooting guns has been done before but not the ability to rip a world The imagery is driven by Valve Software's new Source engine, available for licensing, which knocks the socks off anything previously.
http://www.valvesoftware.com/sourcelicense/enginefeatures.htm