Pre kids I had a basenji/lab rescue dog, he was wonderful - I've always thought I'd get another rescue dog but several people at the dds' school have warned me to be very careful: they tell me about disasters they've had, and with young children I need to make sure whatever dog we get is tolerant, easy going, good with kids. Are they right? I know there's so much luck involved 
We're at home a lot, so no problem there (and can pay for a dog walker if out for the odd day later on) and the girls are 4 and 7. The little one is nervous of dogs that nip and jump up, so again - gentle is good, though obviously all puppies are likely to do both those things for a while, I suppose.
What breeds would you recommend, O wise women of the doghouse? Twice daily walks easy for us, but not hugely long ones most of the time - just from a time point of view. Medium or small dogs best, too - we have a decent sized garden. Should we think about gender too?? Feel so clueless, not sure where to start!