Fox Interactive and Monolith's masterpiece, NOLF is a swanky FPS set in the 1960's. Based on the Lithtech Engine, you take the role of Cate Archer, probably the first female protagonist in a FPS, and a girl with so much groove that I can't even make a bad joke about it...
From the box itself, you can tell that this is the Austin Powers of FPS - and it is a refreshing thing indeed! From beautiful 60's costumes to over-the-top villains (a kilt-wearing demolitions expert, anyone?), the game is the most original thing in the genre. The cutscenes are delivered in a movie-like manner, further adding to the atmosphere. The dialog is perhaps the best part of the game. Where else would you overhear an Arab trying to sell a monkey to a terrorist?
The game has 60 levels in 15 missions and is a mixture of the stealth-fighting of the Thief series and the normal shoot-'em-up of most other FPS's, combined with truly excellent AI.