I could care less about IS for photos at this FL and I know I won't miss the extra range (scanning the exif of all my top shots from the 24-105, very few were 70+).
My concern is video. I do use video from time to time for personal use with my children. The 24-105 is a great video lens and I do worry about the loss if IS there. Can anyone provide input about the 24-70II in terms of 'on the go' video?
I am ready to pull the trigger, but this is my one hesitation.
I'd say the Tarmon is better suited if video is a must. Try using your 24-105 with IS turned off to see how it looks.
Personally i find i can do it but find even the slightest movement bugs me, so i tend to use my Powershot for video on the go.