What do you think the best FPS series was this generation?

I think it was by far the Halo series, being able to maintain excellent gameplay with great story, and creating a massive expanded universe.

Prefered Half-Life myself, mostly because of the evolution between HL1 and HL2. HL1 was great when it was released as it gave some serious story elements to an FPS game. When HL2 was released, it really ratcheted things up a notch with the use of the gravity gun for exploration, defense and offense capabilities. Kinda saddened that HL2:E3 is nothing more than vaporware at this point, and it will be released on "valvetime" which can be anywhere from now till 2025+.

Borderlands.
Both are great, but especially 2.

Halo FTW

Tis the only game series, other then Elder scrolls, that I`ve stuck with for 10+ years And as you said it has a nice balance between story line,game play and game universe.

I personally really enjoy the Bioshock series, the only linear single player FPS that I can actually entertain playing for more than 30 minutes.

Bioshock.

I did like the first FEAR more than any Bioshock game though, but as a series FEAR is pretty weak. Each game got noticeably worse and the third game is unbearable.

Singularity is another shooter I enjoyed, even though it svcked there was no support for subtitles. Hard Rest is neat too.

And that's it