[quote=BityBabyNurse;128729]viking, have you tried the Canon EF 24 - 105 mm F4.0L ? Which one is better, that one has image stabilization vs. the Canon 24-70 F2.8L ? Of course for what I'm using it for, mostly squirmy kiddies.[quote]
I've not tried any Canon lens - I'm a Nikon user
Not that that is relevant: for your intended subjects, I'd choose the 24-70 f/2.8L instead of the 24-105 f/4... VR only becomes useful to steady shaking hands when shutter speeds drop below the reciprocal of the focal length - so on a FF dSLR such as the Canon 5D, the shutter speed would need to be below 1/105 second when fully extended, and below 1/24 second at the other end.
This would be counter-intuitive to the typical shutter speeds needed to freeze the motion of kids at play where you'd want to set 1/125 or faster.
The 24-70 also allows you to shoot and focus in much lower lighting conditions, and the image in the viewfinder will be brighter as well from that extra stop of light vs. the 24-105. Another benefit is the added control over depth-of-field and, reportedly, the 24-70 lens is quite sharp even when shot wide open at f/2.8.
Then again, you're asking a lens whore whose entire kit comprises of f/2.8 and f/1.4 glass with one exception - an ultrawide f/4 for landscapes, so naturally I'm going to be biased towards the higher end products