While companies like Gefen have put a lot of effort into making high-quality wireless HDMI solutions, there are still some obvious limitations. Full 1080p video at 60hz, which is the standard the HDTV industry is pushing towards, takes an obscene amount of theoretical bandwidth. Uncompressed, this 1080p video stream would require about 3Gbps of bandwidth to stream. Compression schemes are extremely common in the realm of high-definition video, and they reduce this requirement by a large amount, but even a fraction of this number is still more than most wireless solutions will be able to handle. As a result, there is no current wireless HDMI solution that can provide 1080p at 60hz. The best you will manage is 1080p at 30hz or 1080i at 60hz. This is still quite good, but it isn't up to par with the quality of a wired connection.
Price is also a serious limitation. Surfing Newegg, you can find numerous so-called HDMI solutions which retail for between $100 and $400 dollars from companies like common wireless networking companies like D-Link, Linksys, and Netgear. These cheap boxes all use 802.11g, and are technically capable of streaming a video signal from a HD source to an HDTV. Their marketing as wireless HD devices is somewhat deceptive, however, as these products are rarely capable of 720p, much less 1080p. The high quality products capable of 1080p at 30hz, like the GefenTV, cost near a grand.