I certainly wouldn't think that just because "GameFly" is trademarked that the point in a website called "Game Fly News" wouldn't be worthless. I mean a company can't trademark a word per`se. It's the English language. Game Fly News is good, but you'll just have to find someone who values gaming news. One thing you will have to watch out for though is the actual intent of the site being news, and not being a ploy on game rentals.
Well, certain words are trademarked, until they become part of everyday use. Like "bandaid" it's really the brand, became known as the sticky adhesive that protects open wounds. Once bandaid became generic for protective adhesive over open wound, the trademark was gone.
Trademarks usually represent the brand, so as long as you don't impede on what they are directly doing, I don't think it's of any consequence, and might prove to be worth something.
The moment you try riding the coattails of an established brand by using their trademark in your name, bad faith is established and to a lot of UDRP panels, that's the nail in the coffin. Best to avoid.