The Orange Box is the best deal you can get if you are a gamer that is on a short budget.
Half Life 2 & Episode 1: I played these two before I got this package but I didn't own them so I am just mostly using HL2 for mods.
Episode 2: I didn't care for the beginning but it has one of the best endings in a video game ever. I found myself personally angry at what happened at the end that makes me hyped for Episode 3. This one is a little more challenging and I felt like I had to do impossible tasks by myself. Every a rebel soldier would help they get killed. I don't like that at all its a war, and it felt more like Gorden Freeman is a John Rambo want to be.
Portal: Wow!! Just wow... I think this is the best game when it comes to game play. It's so different and original it's hard not to like this.
TFC 2: The buggiest game on the list. But graphically I think it really delivers. But this isn't for everyone and I think this might be the least liked game in the list only because its only multiplayer and sometimes playing online isn't so great. But it would have been nice if you could create your own match setting with bots.