Best photos for around the house -for me- are 50mm, as you can get close or far, but use aperture to control the sometimes messy background. Izzy is going to be two in October. I did not mean to hijack your thread, but thought maybe an example would illustrate better than a thousand words. specially with super wiggly kids. 
There is a Sigma 24-60 thread and while everybody loves this lens, there are a small number who have had to send it to sigma to get it calibrated due to focusing issues. Fortunatly mine came tack-sharp out of the box. 

