Ive never heard of anyone using them with PCs, I only see suggestions for soundcards. I have a spare room Im converting into a little theater/video game room. Right now I have a Creative soundcard, but AV reciever seems like a better choice.
Because that isn't a straight issue of PC with receiver. First off, most PC gamers don't just game on their desktops, they also work on them - that means blowing up Office with Lightroom or some rendering program on a single 42in display isn't exactly as good as multiple monitors, or heck even just one. Second, using a huge TV can limit the performance on a computer in many ways. Off the top of my head, refresh rates aren't as fast as monitors, and that split second you're aiming at something might not be where you think it will be (ie he's already there, if you're leading the target), which in most situations wouldn't really matter but to those in competitive scenarios, this can be important. Second, given you have to sit farther away, chances are you'll need wireless peripherals. Some have latency issues, which if you're up against a computer isn't a problem, but can be in competitive scenarios. Even then, while it's easy enough to find serious wireless gaming mice with the necessary ergonomics (and buttons), it's not the same for keyboards. And then, if you're worried about all this for playing against other humans, you still have to set-up the sound so that sound outputs via HDMI on the GPU - which in some cases does not have all the features, like compatibility with all surround sound formats (or they work with games since they use basic formats and mp3, but might not with some BluRay discs' audio tracks) - while you need to run some kind of input for the mic, which will either involve long cables or some expensive wireless solution (which in most cases would have included an entire headset).