Gaming Suggestions For A Non-Gamer?

StephenLegge asks: "I'm a 33 year old computer programmer and I have not played video games since X-Wing came out. My wife is going away to visit her mom for a *month* and I'm thinking about getting a video game or two -- but I hardly even know where to start!" What games out there would you recommend for a non-gamer, especially those must-play-because-they-are-the-greatest games that are out there? We wouldn't want Stephen to miss out.

"If I rent a machine from Blockbuster, should I get an X-Box or a Playstation 2?

What's a killer:
- action game where I can play a spy or a soldier?
- driving game where I can race around in cool cars?
- D&D style game so I can re-live my pubescent RPG days?

Thanks."