I don't know about the rest of you guys. but maybe they are short for a reason.

For example, by the time I got to the last level of Halo 3, I just wanted it to be finished even though it only took a few hours.

In Gears of War 2 it just started to drag out towards the last level and once I finished it I had no need to go back to it again.

The nature of most of these shooter games is that they rely on multiplayer, because they can only keep the gameplay in single player fresh for a few hours before it becomes overly repetitive and boring. I mean lets be honest, most shooters are the same in the first level as they are in the last level, just with a few more enemies and different scenery. Every shooter that lasts longer than 5-6 hours usually has gameplay that changes a lot as you go through (See Bioshock, Metroid Prime series). All others are just aim, shoot, run to next room, aim, shoot, run to elevator, aim, shoot, run through the corridor.

As long as its a Call of Duty, Gears of War, and Halo then ill buy it. Ill just rent something else.

Something is not correct here.....

I find when reviewers give a game x amount of hours gameplay I can double it.
I mean I reckon either these guys get cheat codes or I am crap. :)

For me there is nothing more satisfying than just getting into a game.
I mean the buzz of sitting there and wondering what the f**k do I do here.
I think if a game ends before you want it to it means you have played a good game.
Lets be honest if you are bored a hour can seem like a day yet if you are enjoying something time seems to fly.

Yeah I think he meant either Shooter or TPS.  Gears gets confused with FPS so much though because it really does play like an FPS for the most part and when you aim it is almost the same view as an FPS.  Who knows

Boy... aren't we the picky ones today guys.

Good thing I didn't cite Prime 3 as having the best campaign of any "FPS" this gen... all hell would have broken loose! 

It all depends, like Barozi said, the difficulty definitely ramps up the hours.

For an FPS, I find 7-10 hours ideal for a single player campaign on average difficulty. Max difficulty hourly range of 9-15 would be great. I think the Halo franchise accomplishes this, as well as the COD series. The mulitiplayer is the bread and butter though.

Any game over 10 hours drags on in my books...except Half life 2. that game was awesome...

Bioshock perfect length AND quality.

I primarily play jrpgs so if a campaign could be about 80 hours?....

na that's just not going to happen i'm afraid. in all seriousness something like 7-8 hours is fair for a FPS as long as it has online features