What many people forget when the low light focus capability of the 5DII is discussed is that at the end of the day it is contrast that is more important than the overall light level. The earlier poster saying he couldn't focus on kids dancing in dark surroundings is typical of a low contrast stuation which would be very difficult for any camera. The candle lit scene above has lots of contrast around the candle and is easy peasy for any camera to focus on (assuming a modicum of technique).
Having said all of this, my advice to the OP is to stop obsessing about kit and go out and start earning some money with his current kit/taking some serious photos now, if that is what he seriously intends on doing. If it isn't then his current camera is fine anyhow. Then he can pay for an upgrade IF he needs it based on his EXPERIENCE of what features he has discovered he is missing.
I love kit as much as everyone else and have spent days looking at top end cameras trying to convince myself I NEEDED one, but in the end I started off with what I had, a 40D, and used this successfully for some months to start a photography business earning good money. I then used some of my earnings to buy a 2nd (2nd hand) 40D as backup as I realised that this camera did everything I needed and I could have both bodies configured identically. About a year later I had some situations where the 40D could no longer cope (fast moving subjects in very poor light) and used my earnings to buy the best option at the time which was a 1DmkIV. I love all three bodies, I still use the 40D for 70% of my work (and for personal photography), but for the other 30% I get results with the 1DmkIV that you simply couldn't come close to with a lesser camera.
Once you have the experience of what, if anything, is holding you back - and you are CERTAIN it is not poor technique - then the choice of what to buy becomes a lot easier.
But then if everyone took this route the equipment manufacturers would go out of business....
Oh, and forget the DSLR for every day video, a £150 camcorder will do a better job and be much more fun to use.