I'd be amiss if I didn't mention something about the new Metal Gear Solid 4: Guns of the Patriots. Having not played it, my position isn't really informed on the game itself, but the game's reviews bring up a lot of issues surrounding the gaming industry.
There's a lot of back and forth regarding some of the scoring assigned to MGS4 out there. Some sites, such as Gamespot, IGN, and 1UP have lauded the game as an unrivaled convergence of gaming and art. Some, such as Penny Arcade, have derided the game as having several personalities, with most of them being near-utter failures.
It's very difficult to score games. There are analogs in movie and music reviews, and of course in all other art forms. Even if you don't believe video games can be artistic expression, as they almost certainly are in some cases, they are definately entertainment, the same as our popular art forms. As hard as it is to grade a movie or CD, something that may last an hour or two, it's even more difficult to score a video game, something that people experience for hours, days, weeks, or years.
As a gamer, while I read reviews, I don't simply rely on absolute scores to determine the worth of a game, or whether or not I will play it. I'm always going to play a Command and Conquer or Star Wars real time strategy game, even if they get a "6" or "two of four stars" because I love the franchises, and I'm a fan. I'm probably not going to play Metal Gear Solid 4, not the least because I don't have a PS3, but not because it got this score or that. It's because I'm not a fan of stealth-combat games, in the genre of Splinter Cell or others.
When I recommend games, I can only speak from my experience. If I had fun with a game, I tell a friend why I liked it, not why I think he or she may like it. That's why as gamers, and those who read or write video game reviews, we should take scores as they are, not objective measures of market wealth like an auction price on eBay. Rather, they are subjective things, an all-too-human attempt to quantitize the unmeasurable.
In the end, we can only ever truly know what we know and experience as individuals. My experiences are my own, played through my eyes, controlled through my hands, endured by my body with a small child bouncing off of it. Your 4.5 might be my 10.0, your A+ my F-. Don't take it too seriously; scores are simply an attempt to convey unknowable experiences using language, imperfect as it is.
Play Metal Gear Solid 4 if you can, and be richer in experience for it, love it or hate it.