I'm sure this has been addressed before but here goes anyway:

I have a question about the image stabilization lenses. I only see Canon IS lenses listed for the long lenses like the 70-200 but not for wide or mid range zooms like the 24-70. Though the APS lens for the 7D 17-55 is an IS lens. I don't see it for the normal or shorter tele lenses though it is on 17-55.
How come? When do you start needing the image stabilization.

I just ordered a Tamron 17-50 VC lens. Was the image stabilization a waste of money?

the 17-50 range is probably the one you would most ofter use handheld, so the IS (if you ever shoot without tripod) will definitely be useful

If you are recording sound, the image stabilization system might be noisy.

I have the Tamron 17-50 non VC and wish it was the VC version (great lens though). I will eventually get the VC version.

The IS or VC is important, I bought the Tamron 17-50mm VC just to get the image stabilization. I already owned a Canon 16-35mm L. The Tamron and the Tokina 11-16mm make a great combination for the 7D.

The IC/VR lenses hold the biggest advantage with telephoto lenses of 200-400mm range on full-frame bodies like 5D/D700 or 180-300mm on 7D/D300s; although this mainly applies to stills because tripods should always be used for video when using these telephoto lenses and IS turned off.

When using wide-medium telephoto for video it all depends how steady you are at hand-holding cameras. In steady hands IS is not really needed for anything wider than a 28mm lens (full-frame equiv), so lenses such as the non-IS Tokina 11-16mm will provide smooth and steady stills & video in most circumstances.

The IS lenses should not be used in combination with a steadicam/glidecam, and you'll get far better results with the IS switched off.

However, at the longer end of lenses such as the 24-105mm IS it can sometimes help, especially when on a 1.6 crop factor body like the 7D; although Norman's comments need to be taken into account if you are using in-camera or onboard mics.