For a "Grand Theft Auto" and "Forza" video game aficionado, it's impossible to think about what the gamer would do without Xbox, Wii or PlayStation. Not to mention, the avid gamer simply must be able to buy newer titles like "Medal of Honor" or "Call of Duty" as soon as they go on sale. GameStop takes the guesswork out of the whole process, thanks to its in-store promotions, newsletters and pre-order game notifications on its website. This worldwide retail chain with over 6,000 stores ensures that its customers are always happy gamers: In addition to selling video games and consoles, it buys previously owned games too.