What exactly can be affected by a 2.4 Ghz wireless phone? Something like a Sennheiser wireless receiver? A Mac airport? Anything else?

And is there really that much more clarity and less interference in a 5.8 Ghz phone?

Just wondering what peripheral wireless devices might be affected by a phone or other wireless devices in a studio environment.

There isn't as much equipment operating at 5.4ghz right now but the operating range is shorter than 2.4ghz. Noise and clarity isn't an issue with either one.

Cordless phones do effect my airport network. It's actually a bit of a pain with my laptop (marginal antenna).