Great reason to get an X-Fi if you use headphones

We all know how awesome surround sound is, but you can't always have that option, since surround sound is often best heard turned up LOUD. It also requires the space for a surround speaker setup. A really good alternative is wearing headphones and selecting hardware accelerated sound such as EAX or directsound3d, provided by the X-Fi or any other sound card supporting such formats. The biggest issue with this is that not all games that support multichannel sound support hardware accelerated 3d sound, or support hardware 3d sound, but it either sounds crappy because of a bad implementation or has various problems such as the loss of headset support or unexplained noise, due to glitches.

As an alternative, you can use the CMSS 3d Spatializer on the headphone setting provided by the X-Fi and tell your games to output software-based multichannel sound. The spatializer will then create a virtual surround system, giving you surround sound on headphones, without having to drop a fortune on a 5.1 headphone set that most likely has crappy sound quality, is uncomfortable, or has terrible acoustic isolation. You have the freedom to buy tried and true 2 speaker headphones.

I use this method personally, and it is vastly superior to the 2 channel or headphone sound option in games that don't support hardware 3d sound, or support it poorly.

Half-Life 2 is one game that benefits greatly, I should say. Especially with its 7.1 option.