Can anyone say if they back button focus with the image stabilization turned on for a 70 200 2.8? I'm just curious if the norm is to just shoot away like this. Thanks

Yes, and Yes.

I *now* use the back button for focusing on my 5D. I say "now" because I started using it just a week ago. I was scared to switch, but I LOVE using the back button.

I also shoot with the 70-200 IS with the IS nearly always turned on (heck, I haven't been able to use that lens in well lit situations, yet) and I haven't noticed a problem. You feel the gyroscope moving a bit, but it doesn't do the image stabilizing thing until you actually press the shutter button all the way down. I think. At least that's what I gather from the shots I take and from the feeling of the lens.

Just keep in mind that people shake, even if the camera doesn't. I ruined about 100 photos last sunday with people movement. Got that sick feeling, you know?

Hope that helps.