Actually, if you're not a stickler for picture quality and you have a wireless connection then the Nintendo Wii is actually the best thing for watching internet video on your television. Surprised? So was I. But it's honestly so awesome, it almost makes the console worth it on its own.
This is possible through the combination of a few things. Wii + WiFi + Internet Access + Wii's Web Browser + www.alluc.org. Ok, it sounds more complicated than it actually is, but most people already have Internet Access and a Wireless home network, so those are just standard requirements I wanted to get out of the way. It's really simple. All you do is load up the Opera browser on your Wii, head over to www.alluc.org and watch whatever the heck you want, full screen, instantly and in real time. It's freaking FANTASTIC.
Actually, if you just want to watch stuff on your computer when you're bored or just want something to do, they have pretty much every single episode of all popular shows up there, along with a lot of popular movies (though they're a lot better with shows).
In fact I think a lot of these new media streamers coming out in the future will start interfacing with YouTube and other video streaming sites. Heck, a few of Sony's Bravia televisions that they'll be launching later this year will come with an ethernet port where you can watch internet content directly from your TV using grokker or grobber, I forget the site's name, and Sony's own video service.