Price fixing is a nebulous term. Horizontal price fixing is where two entities at the same level agree to set prices. For example, Alice and Bob both sell widgets, and they agree to sell widgets at a higher price than the market price, making “extra” profit. This type of behavior is per se illegal.
The case with video games is different. It’s vertical price fixing instead of horizontal. As mentioned in the wikipedia article, this kind of behavior is based on the rule of reason, which is an economic analysis of the behavior to see if it actually harms consumers or not (which is the end goal of antitrust law).
Video games are an especially good example of beneficial vertical price fixing. The goods are fungible – a Wii is a Wii, no matter where you buy it. Games are the same way. The question to ask then boils down to if the price restraints hurt competition. They do stop price competition, as Wal-Mart can’t undercut Best Buy. On the other hand, it keeps Wal-Mart from undercutting businesses who can sell the same product but just don’t have the same market power to get volume discounts, etc. There is also another vertical restraint that is possibly more important but less obvious – release dates. Stores that break street date get a LOT of sales, at the expense of other retailers. Enforcing street dates are important to keep all of your other customers satisfied by not giving an advantage to some retailers and not others. The benefit here is twofold.
First, Wal-Mart can’t be THE place to go for Xbox games and then use that power to guide the market – for example if 90% of all games get sold at Wal-Mart and they refuse to sell violent games, violent games are going to become scarce.
Second, the vertical restraint drives competition in other areas, like customer service or bundling. An actual real life example of this is the Xbox 360. For a while they were a bit scarce, but prices were fixed. Thus retailers started offering bundle packs - buy an Xbox get a game or get twenty dollars off of a controller, etc. Note that it gave customers a better deal both on bundles and since demand had outstripped supply, 360s would sell for higher than the set price in a free market.
There are a few other benefits as well, and a couple of drawbacks, but these are kind of the major ones. The Leegin case explains in better detail the rationale behind allowing reasonable vertical price fixing. Also important to remember is that the vertical restraints WERE illegal before Leegin (which was not so long ago), and enforcement was sparingly used. I’m guessing that the harms to the consumer were not high enough to justify going after the video game industry when there were far more harmful actions going on. Either way, the industry can’t get too out of line or their restraints will cease to be reasonable and they will be in violation of antitrust law. In my opinion, the game industry actually does a pretty good job for consumers in most cases (Madden football’s NFL license being a glaring exception).
On the other hand, there are a lot of good arguments AGAINST allowing vertical price fixing. The law at the moment is to allow it if it is reasonable, but it is still controversial.