Comparing game ratings from two different people are pointless. One man's 7 is another man's 5. A single man's rating is pointless unless you get to know how he rates other games. There has to be context. If I say the temperature is 50 out of 100 and I tell you that 100 is as hot as the sun, you still don't know what it means because you don't know how cold 0 is.
Comparing ratings from two different sites, same thing. Site ratings vary.
Only reasonable way to use an individual rating is that each number represents something. There should be a list of what requirements a game of rating X must fulfill. Stuff like Metacricit scores are useful to get a rough estimate of the quality of a game. Still, id doesn't really tell you anything concrete.
To be honest, Brad is probably right about the Metacritic score. As he pointed out, even MOO3 got a 6.4 in Metacritic.
I'd just like to remind people that there are a number of points that render individual critic ratings next to completely useless. It's the text you want to read. They do have power behind them though, the numbers affect the general public, and therefore sales.
I'm quite surprised that there are so many people here wanting to throw out some random number without any context.
As much as Trojasmic's opinion is subjective, at least he gives reference points to the scores.