I can tell you from experience that there are times when using a HDMI cable for your home theater just won't work. I have a projector in my game room and it's about 14-feet from my cable box. The thought of having to run a HDMI cable up the wall and across my attic floor was none too appealing to me. I ended up going for a wireless HDMI adapter from Rocketfish and it works very well.
If you have a setup where your cable or satellite box is a long way from your TV or projector wireless HDMI is certainly a viable option. ZyXEL has a new wireless HDMI system called the Aerobeam WHD6215 that includes the wireless sender and receiver that has now landed for general availability. Interestingly it looks virtually identical to the Rocketfish wireless HDMI system I use. The ZyXEL WHD6215 is the same price as the Rocketfish system at $199 normally. The WHD6215 system is on sale at Buy.com though with a price of $180 from August 15-30.
The ZyXEL system will work with any HDMI device and shoots the wireless signals to the receiver connected to your TV or projector. The wireless system supports full 1080p HD resolution, 3D, and 7.1 surround sound. It uses 60GHz spectrum for beaming the signals to avoid interference and has all the bandwidth you need for streaming wireless HD. ZyXEL is mum on how many HDMI ports the device offers.