I owned a Canon EOS T2i/550D for the last couple of years and have been shooting both still photos as well as video footages out of it. With it's price range (below $1k) it's been delivered a great images thus far. Though in low light condition, you couldn't really compare it with 5DMrkII (or the new MrkIII) but for web content quality. I think T2i does deliver pretty decent low light video footage.
Now that Canon release the latest EOS T4i/650D. I have been looking out for reviews online. What I find is pretty impressive actually. According to this video. Low light video footage from this camera has been greatly improved. (Though I can't really judge much from Youtube video) still it's look pretty decent in my opinion.
Also new features overall in this camera is pretty cool. hybrid CMOS sensor, touch screen. (Very fancy and come in handy), low light NR, build-in stereo mic, dedicated video mode switch, auto-focus in video mode and the new STM lens. (that 40mm pancake STM lens looks sweet!) I would definitely recommend this camera for folks who couldn't afford 7D or 5DMrkII or 5DMrkIII. It's definitely great alternative. You saved on the body and invest more into good lenses. Can't be disappointed really.
Disclaimer: This comment above is intended for low-budget folks only. If you have ability to spend on 5DMrkIII. By all means...go for it. I love that camera too. I just couldn't afford it. =(
Remember, camera is just an instrument. It's YOU who make all the shots look good. =)