I would say go to the animal shelter after doing some general breed research. Don't pay for a pure bred when there are so many dogs that need homes. I've been a Vet Tech for 6 yrs and have seen many breeds. Regardless of the breed, all dogs have different personalities and can have a bad day but there are some breeds that typically are NOT good for kids: terriers (too hyper and high maintenance), dalmations (same), border collies (great dog but need alot of play time), cocker spaniels (likely to bite/turn on a dime) and even Corgis are known to bite (they bite the Queen of England)...
You need to think about size and activity level. If I were to get a dog right now for my 10 and 6 yr olds it would likely be under 30 pounds, no flattened nose (too many health/breathing issues) and not require alot of training, ie: a mix or, Yorkie, Beagle, Eskie (american eskimo), Mini Schnauzer, Cavalier (expensive though)...
Good luck