Which should I buy XBOX 360/ Playstation 2/ Wii?

Should I buy XBox 360, Playstation 2 or a Wii? I'm not really into the gaming world so I need help. The games I really want to play are Guitar Hero, Grand Theft Auto, and Halo. So which gaming system is the best? I want a game system that will last a long time and have new games coming out for it for years to come. I dont' want to spend all this money on something that will be obsolete in 3 years.