Half Life: Episode 3.
I got the orange box and took a couple of weeks break from BF2. HL is so different from every other FPS, in that it has a solid story, engaging characters, and a plot that is more than just an excuse to shoot stuff. The next chapter should be really good seeing the effort Valve put into producing their games, and there are so many questions it'll answer, like how portal ties in to the main story line.
There's Crysis and CoD4 out real soon, but they're just more of the same FPS fodder with better graphics. The HL series is feeling more like a set of good science fiction novels made into an interactive film (like books are ever made into decent film versions anyway).