Okay, while it has been proven that many games use colours, the obvious reason for not using colours is wanting to have a sad theme.

If you look at for instance SMG, that's a game that shall have lots fo colours and such, because it's supposed to be a happy, not to serious game.

Now look at Zelda, still a game with a happy theme, but not as much as SMG, because there are some sad stuff.

Then you have Metroid Prime, a war game, but not really realistic, so it has some colours, but not a lot.

Then there is the "real" war games, where they use grey (gray is accepted though) to make you feel a bit... depressed, so it fits the theme.

I used a lot fo Ninty there, because those are the games I've played. I guess you could change SMG to R&C/LBP, Zelda to Prince of Persia or oblivion and Metroid to Halo.

That's warfare in a different context genius , I was specificaly reffering to games like Killzone hence the use of the game title "Killzone".

jeese guys, if you don't like that sort of game DON'T BUY THEM. there are plenty of HD games out there with plenty of colour. if you want to know why 'serious' war simulation/FPS games are so grey/brown, watch a movie like 'Starlingrad', you'll see why these war torn cities are so grey and dark - hence why the games are too.

of course, if the game was based in a jungle, you'd get very different colours. so stop moaning about it and go play your own systems with the sorts of games you like to play, and HD FPS junkies like me will stick to our drab grey games, because thats what we want.

 I agree. I remember Quake I and II (and lots oftheir clones), that at their time were the top for graphics, were mainly criticized for being too much brown. The use of dark colors, IMHO, doesn't really add realism, but perhaps may help to avoid diminishing it, because it may mask some flaws, and if we weren't absolutely near photorealism at Quake times,  it hasn't either been reached now with HD,  indeed, we are certainly closer than 10 yrs ago, but there's still a lot to do.

Because of this I tend to prefer fantasy settings, somehow they make games developers less afraid of colours.

Also jungle war settings are fine to me,  they force designers to use some colour (OK, mainly green, but it's a change anyway ) instead of the same ol' grey and brown.

 I find it odd they pick skate as an example of this "Realism = Bland" trend when I think EA is probably one of the few companies who seem to make games that both feature "realistic" graphics and keep things lively visually. The whole gritty thing is more than just color choice for me, that's just one of the more noticeable things. Here's a screen from Rainbow Six: Vegas.

And here's skate. 

Rainbow Six: Vegas certainly had plenty of colorful areas in the game. But I found the visuals kind of dull when I played it. It felt muted, I guess. The colors actually don't contrast with each other that sharply and the lighting seemed to create a kind of weird haze that made things to blend together.

Things in skate always looked more vibrant to me than in Rainbow Six, even if gray was a dominant color. Even the roads seemed more lively.