I used to use the 70-200 f/4 (non IS) and a rebel to take pictures of my son when he was a baby and daughter when she was small. I later upgraded to the 70-200 f/2.8 IS, and later the 70-200 f/2.8 IS II (by then my kids were bigger )

The 70-200 f/4 was fine for outdoors, but required a little too much light to use indoors. I used the 70-200 f/2.8 IS both indoors and outdoors, and never felt like it was too long, even indoors on the rebel. I guess I prefer a little more working distance than Scott.

Opinions vary, and as I said, I know I'm in the minority here.