I voted computer, game console, smart TV, and other (iPad and Android phone). If I were to put that in order of what I most commonly use, it would go...
1) iPad 60% (Crackle, ABC Channel app, History Channel.com, Home Theater Geeks episodes, NHL.com, ESPN360, YouTube, Flixster, etc.)
2) Computer 30% (same as iPad)
3) smart TV's built-in apps 5% (movies and TV shows from Crackle, Vudu, and Amazon Instant Video)
4) Android phone 4% (primarily sports highlights and videos people send links to via. Facebook)
5) Xbox 360 - 1% (used it to stream a TV show using Xbox Video once)
I also redeem the digital copies included with my Blu-Ray purchases as downloads from the iTunes store when available. However, this isn't technically streaming so I didn't include it in the percentages above.
Are you planning to do a poll asking people what devices people use for streaming audio as well? If you include that, I would add my AVR to the list. I typically stream audio from Pandora, iTunes Radio, and TuneIn Radio, though I have also used iHeart Radio, Slacker, Rhapsody, Xbox Music, and a few others in the past. For the music I own, 99% of it was ripped from my CD collection, but I have started downloading music from iTunes in the past year since the quality has gone up and it has become harder to find the actual CD's in a store. I could see downloads becoming my primary means of acquiring new music, but it will take something like 20+ years or so before the number of tracks I have downloaded will equal the number I have on CD, assuming I download over 150 tracks a year.