Im kind of both sides of this one...
I do believe that the ESRB rating is there for a good reason and it should be enforced, nobody under the age required by the ESRB rating should be able to buy the game.
Not that I think "depraved violent" video games or ones that contain "indecent images" should be the end all of things. Its a fact that some people are predisposed to violent actions and a video game is hardly where it all begins. Not everyone who saw "Jackass the Movie" for instance went out and did a stupid stunt that got them killed (though many did) it sort of brings weight to my point that censoring certain things is not going to stop people from being violent or doing stupid things.
I think all they need to do is start enforcing the rules rather than making new and harsher punishments. Just the other day I saw a young kid at Target buying STALKER, the kid looked as if he was barely into his teens but yet the cashier took no notice of the "MATURE 17+" sticker with the giant "M" in the middle, which is part of the ESRB rating. I think instances like this are grounds for large fines for retailers or loss of employment for the cashier allowing the person to buy the item. A guy sells alcohol to a minor faces much worse, as does the store that employs him.
But the bottom line in my mind is still the parenting. If you dont want your kid playing a violent game, dont blame the company for making it or the cashier for selling it to your kid, blame yourself for being to stupid to realize the obvious. If you dont want your kid to buy the game, dont put his ass in the back seat of the suburban, dont drive him to the store, dont give him a $50 bill, and dont let him walk in and buy it by himself... Its costs a lot less and is much more effective if the parents take the step to censor their children from what THEY believe is wrong, rather than to censor the whole country who may not agree with your beliefs.