I don't understand why it has become indoctrinated that FPS is a genre of video game in it's own right.

The 'FP' in FPS stands for 'First Person'... this has nothing to do with the genre of the game, it is a game mechanic. It's like using the difference between 2D and 3D platformers and calling them different genres. It's prefectly ok to seperate between the two because they have different gameplay mechanics, but Super Mario Galaxy and Super Mario Bros. 3 are still both platformers. The 'S' for 'Shooter' is something that you do in the game, it could be argued that as the game is about shooting that Shooter is a game genre. Personally I don't see it that way for any game that has a proper story or varied gameplay, a shooter as a genre would be something more akin to asteroids or galaga where all you do in the game is shoot and move about. Alternately many games are cross-genre so it's perfectly possible for something to be both a shooter and an adventure game. Either way it cannot be argued that Metroid Prime isn't a shooter.

The genre of a game is what it's about... For me the majority of FPS games are in the vast genre called Action games. Action games encompass a wide variety of sub-genres such as shooters (in both FP and TP camera forms) fighters and platformers.

Metroid Prime series is still an FPS, but it's in the Action-Adventure genre instead of just Action.

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I haven't played it but isn't Bioshock an FPS-RPG (maybe to less of an extent than Deus-Ex, but I thought it had enough RPG elements to be different from normal Action FPS)

Also Portal is still an FPS, but it's a Puzzle-FPS

Battalion Wars is in Third Person but if it were in First Person perspective it would be a Strategy FPS.

Doom 2 baby.
Almost no story, but the levels just flow one after the other.

Edit: So as a series, the old DOOM games.

Later edit:
Freekin specify the era if your thread title is explicit enough to answer directly damn it.

I'm one of those crazy guys who still believes in reading the OP, so no.

How dare you compare Call of Duty to Bioshock, Call of Duty is nothing in comparison. IMO

I believe in correct wording, so I still believe you shoud.

Half-Life hands down

I won't. I'm perfectly fine with the current wording.

The only reason why anybody claims that MP isn't an FPS is because of Nintendo's marketing BS. The FPS genre has many games that stray further from the core mechanic of shooting things in the first person (Deus Ex, System Shock, STALKER, No One Lives Forever, etc...) that are still considered to be FPS games. Remember that a game can exist within more than a single genre.

My top 10:
Half Life 1
Bioshock 1
Halo: CE
Half Life 2 & Episodes
Perfect Dark
Goldeneye 007
No one lives forever 2
Call of Duty 1
Medal of Honor: AA
Halo Reach

So Half Life wins as series.

I don't like call of duty that much, it's an okay game. But I sort of mistated, it's shooting mechanics are  quite a bit more polished than bioshock imo. Bioshock, is kinda clunky, but so is deus ex (the original) and it's my favorite game.

I rate CoD like a 6 and Bioshock a 9 so don't worry.