Some of Roger Ebert's personal ethics guidelines:
"No posing for photos! Never ask a movie star to pose with you for a picture . . . . . . You diminish yourself by asking for a snapshot."
"A trailer is not a movie."
"Accept no favors. For example, if some 'friends' throw you a birthday party at a Vegas joint they hope to fill with movie stars who are your 'friends,' say thanks, but no thanks. That crosses the line, even if the 'Britney Spears of Korea' truly is your close personal friend."
"Keep track of your praise. If you call a movie 'one of the greatest movies ever made,' you are honor-bound to include it in your annual Top Ten list. Likewise, for example, if you describe a film as 'the most unique movie-going experience of a generation,' and 'one of the best films of 2007, and of the last 25 years,' it's your duty to put it in the Top Ten of 2007."
I'd love to see game journos adhere to ANY of these.