Help Me Decide Wich Game To Buy?

I would wait and get the Half Life 2 Orange Box set thats coming out with Episode 2. It has Half Life 2, Episode 1 and 2, Portal, and Team Fortress. I would also suggest downloading this all from Steam if you have a good internet connection as this is a very easy way to get the games. The great thing about Half Life 2 is that it has an excellent modding community and you could literally keep yourself busy for over a year playing just the FREE mods that you can download online. A few that are good are SourceForts, Dystopia, Garrys Mod, and Zombie Master.