While it is good to see a system already in place and being voluntarily adhered to by most major retailers, there are improvements to made.
The main one improvement I think the ESRB rating system needs is some way to distinguish between excessively violent, thought-provoking games (like Manhunt) and more tame games like the aforementioned Halo.
Both games appear the same if you go down a static check list of in game items: (blood, gore, swearing, loveual references) but I think the general public would agree, assuming they tried both games, that both present vastly different motivations and experiences for the user.
The other improvement would be a more fine-tuned ratings system. I know they think all Americans are too lazy/incompetent/<insert other blanket statement that could apply to any significant part of humanity> but describing how much of each element there is in a game.
For example, I have played games which received an M rating and had "Strong Language" in the warning label, yet ingame you only hear one or two bad terms the whole time. On the other hand, you have games like the GTA series which manages to use the term "forget" as a noun, adjective, adverb and verb all within the space of a minute (and throughout much of the games repeats this). A parent wouldn't realize this by looking at the label.
