If you're looking for a completely fresh FPS experience, you will find it in the Orange Box.

User Rating: 10 | The Orange Box X360
Simply, you need to experience the Half-Life series. If you've played games like COD4 and R6V2, and though they were excellent, play HL2. I guarantee you will be awestruck by the cohesiveness of it all. You will find that every character is very believable, you will find you care some characters and really despise others. The world is completely organic(due in part to the amazing physics engine), each locale makes you feel like you're actually there, and not playing a video game. Furthermore, you cover some serious distance in HL2-Ep.2. Unlike most games, where you travel to different areas via cutscenes, in HL2 you actually DRIVE across huge expanses of land in action-packed vehicle sequences. Also, there are NO cutscenes at all, and you never lose complete control of Gordon or the 1st person perspective. Since Gordon never talks, you always feel like you're actually this epic hero in this dystopian world, fighting for liberation. Really, HL2 is one of the more immersive games ever crafted. The organic environments in conjunction with the superb writing and production values really make the world believable.

As for Portal, it has some of the most wittiest dialogue a video game has ever seen. You will constantly find yourself chuckling at GlaDOS's dry, sadistic lines. The portal gun makes for some brain-twisting(for lack of a better word) puzzles, and, surprisingly, the game has a very intriguing storyline that will pique many questions about the protagonist's role in Aperture Science.

Finally, Team Fortress 2, as the multiplayer portion of The Orange Box, will be a completely fresh experience for COD4/Halo/R6V veterans. You will find the 9 classes as distinct in both their visual design and gameplay aspects. Each classes cancels out other classes, making for an extremely balanced game. This means there will be always be a great mixture of classes represented in each game, and that most matches will be virtual tug-o-wars. TF2, perhaps better than any other game, encourage teamwork for success. If you're looking for a team-oriented, unique multiplayer experience, you will find it in TF2.

Here is the final verdict
Production Value-10/10
Fun Factor-10/10

Final score:10/10