In the age of everything on demand, cable TV seem like an antiquated service that should've been retired years ago. Roku just introduced it's Roku Stick, the popular set top streaming content box in a teeny tiny USB stick form. But before Roku releases this miniaturized option, there are still plenty of streaming options available right now...
Apple TV
Apple fangirls and fanboys need to get this, with the introduction of AirPlay on Apple TV, there is one more reason to get Apple TV. Its compatibility with iTunes also means that you can play all your purchases or even rent a movie and have it stream right to your TV. With a number of sports streaming option, this makes streaming TV more bearable for sports fans. And with jailbreaking, you can even get the popular open source media software, XBMC on it.
Set Top Box
Companies like Roku and Boxee have been perfecting the set top box. Our experience with the Roku box has been wonderful, especially with wide array of streaming sources such as Netlfix, Hulu and even Amazon Instant Videos. And the ability to add on many free channels, makes the Roku a closer experience with your old cable TV.
Your Game Console
Popular gaming consoles such as PlayStation3, Xbox 360 and even the Wii have built in many different streaming sources to expand its video offerings. PlayStation3 is even able to connect to your home media server to stream many of your own movies collection. We love the PS3 for its ability to play BluRay, stream from Netflix and Hulu and of course its great gaming selection.
(Image: TOP FALHakaFalLin licensed for use under Creative Commons; APPLE TV Rob Boudon licensed for use under Creative Commons; XBOX360 Jami3.org licensed for use under Creative Commons)

Sprout Side Table
I've been using the XBOX360 to stream media from my computer for years. It works much better than the PS3. I have no problems with .mkv or .avi files. They also just updated the user interface, WAY more "channels" now. Netflix, UFC, YouTube, NBC, etc.
I've been cable free for over a year. I went with a small desktop PC (Acer) with Windows Media Center (WMC). The one thing I couldnt give up was DVR thats why I went with a pc. With a TV tuner and remote the setup cost me about $400. I can still watch and record OTA stations(NBC,ABC,FOX,CBS) and suplement that with Netflix and Hulu that work from within WMC. Canceling cable saved me over $100 a month. Sure there are draw backs. I miss HBO and every once in a while I miss ESPN. But over all I love my cable free tv setup.
ESPN360/ESPN3/WatchESPN or whatever they're calling it this week, has most of the live events ESPN airs. Notable omissions are Monday Night Football and NASCAR, but college football and basketball, NBA, MLB, MLS and European soccer and several more obscure sports and leagues are included.
I lived cable free for about three years, but my wife is unwilling to let go of cable. Even though I love having ESPN and the Big Ten network, I could pretty easily go to the bar for every game I want to see for less than it costs us to have access to shows about cupcakes available every hour of the day.