I don't have kids, but here are my two suggestions.
First - carry. I carry at home, so for me that's a natural solution. Someone comes in my house, I'm prepared to defend, I don't have to run for a gun that I've locked up somewhere. My carry weapon is intended to give me time to get to my heavier weapons should I need them.
Second - and this could be either a full time solution, or one that fits when you can't carry. A springloaded finger keylock safe. I have a little GunVault that can pop its door open in about a nanosecond. It is interior lighted and I can put both a 9mm (Glock or Sig) and a snub nose revolver in it. Here's a link http://www.cheaperthandirt.com/GNS701-1.html Cool thing about these is that you can be shaking like a leaf with terror and still open them, I would challenge you to do that with a traditional combo lock or even a key.
It can be bolted down so that it would be very hard to carry off. I have a friend who drilled right through her kitchen countertop so that it's handy for her where she spends most of her time at home. Mine is right next to my bed, so that I can open it quickly at night, and store my handguns during the day. (I work for the feds so can't carry at work).