Imagine TV in high quality video, personalized based on what you like, such as 24hr mountain biking, or all Formula One races or 24hr celebrity gossip. You can clearly search for the most popular videos on anything, browse by category, or look for the "most watched" but there is not yet a way to get video, completely customized based on YOUR preferences.
YouTube, Metacafe and many other sites became hugely popular based on an immense selection of user generated video content. According to Forrester Research, 15.5 million households watched internet video in 2006, compared to 7.9 million that used social networking sites or 9.4 million that bought and downloaded music files. That's just the beginning - live TV over the internet, consumable on any device, including PC, TV or mobile phone will change how we enjoy entertainment.
In fact, just like major TV stations fighting over TV celebrities and popular TV hosts, video sites are now fighting over the most popular consumer generated video producers. But it will be more interesting to watch the competition to provide customized TV over the internet.
There's excellent coverage of number of different start-ups going after this market in different ways on TechCrunch. For instance, MobiTV assembled a $100 million war chest to go after live TV mostly over mobile devices (they do offer a PC service via AT&T). Then there is ManiaTV which impresses with its unique and live programming, JumpTV which stands out by providing access to a large number of international TV channels over the internet. The traffic numbers clearly demonstrate that these two are winning over other approaches like limited cable over the internet, Al Gore's CurrentTV or old TV programming over the internet. A notable exception is Orb which is gaining popularity by offering your home cable lineup and more via a software download instead of a specialized device like Slingbox.
My personal take on it is that it comes down to quality content, selection, AND personalization. It will be exciting to watch who gets that last one right.