Color is a powerful tool. I don't want to go all MovieBob on you, but game developers could learn a lot from filmmakers. George Lucas* once pointed out how he made the main protagonists of Star Wars wear earth tones. (*I'm talking about George Lucas, the filmmaker who was active in the 70's and 80's, not the famous toy magnate of today. I don't know why, but people are always getting those two guys confused.) The good guys wore warm colors, while the bad guys were entirely black and white. It created a stark visual difference between the two sides. It made the troopers stand out on the sand-blasted world of Tatooine, both visually and metaphorically.
When you see a character driving down the road in a red convertible, take a look at the other cars on the road. They're likely all white and gray so that the car can really stand out. It won't do to have Vin Diesel pull up in a fiery red hot rod, only to have a bright red Prius scoot up beside him at a traffic light.
In The Matrix, the virtual world was tinted green to help the audience keep track of what world they were in. Most people might have not consciously noticed it, but their subconscious did, and that tint was a powerful tool for helping them make sense of a potentially confusing premise.
The colors you see in movies are carefully chosen to set mood, to draw the eye. To denote importance. To make the audience remember an otherwise unremarkable detail. Which is why I get so pissed off when games build a world out of rusted metal and coat it in a layer of concrete dust. They're giving up one of the most powerful tools at their disposal.
If you play through Crysis 2, keep an eye out for what the artists have done to make the scene "pop". Brightly colored cars. The angle of the light. The use of trees to break up large stretches of concrete. Making sure the shadows fall so that the foreground and background have contrast. The game has a few stretches (mostly underground) where things might get a little tiring, but most of the game is interesting, varied, and unique.
Note to other game developers: Before you send your boss over to CryTek with the company checkbook to shop for a new graphics engine, why don't you try putting a little color into your current engine and see what you get?