All of you folks (except maybe Glen) are completely full of half-assed "theories" and fantasy-land stories.
What you should do is a search on the Web for anything written by Tom Nousaine - he is certainly a knowledgable and credible authority on bass reproduction. That guy built a subwoofer system into his house that could almost literally knock the building off its foundation.
But someone did sort of almost make a good point - if you use your subwoofer to enhance your GAMING experience, sound reproduction accuracy is about the last thing you probably care about - simulated mass destruction is the point.
For MUSIC, well that's another story. Here's a technique that is proven to work - experiment! Try putting your subwoofer in as many different locations as you can. See what works best in your situation. Sometimes a corner snug against the walls is the hot ticket. Sometimes a foot away from the center of the wall works better. Every room is different, and it's easy to try different locations. There is no hard and fast rule, but placing a sub in a corner tends to accentuate the bass and moving a sub away from wall/floor junctions tends to reduce the bass.