We have a chocolate lab puppy (8 months old) and she is lovely. I second what people have said about the chewing and the toilet training - it is very intensive at first, though our pup was very quick to learn, and only soiled her cage once, and very soon learned to 'go' outside.
But you do need to be there - every time the pup wees indoors, or looks about to start weeing, you have to whip them out into the garden and wait until they do at least a bit of wee/poo there, and use whatever command you want to for weeing/pooing (ie 'be quick' or 'do your business') so that they learn to associate the phrase with the act, and should be able to do it on command, then when they have wee'd/pooed, reward them and praise them. You also need to take them outside at regular intervals anyway, particularly after meals, I believe, and wait with them until they wee/poo, and do the same process as above.
Also a young pup really can't be left home alone for any real length of time. We use a cage, and now ddog will stay in her cage quite happily whilst I go to art class or nip to the shops, but most of the time I am around so she has company and someone to keep an eye on her.
Also labs will eat anything - and if they can't actually eat it, they will chew it up and spit it out. Since we have had her, our pup has eaten 15 mince pies, steak, salmon, my glasses, four shoes (sadly not two pairs, but four shoes from four pairs), wallpaper, two xbox headsets, 16 rashers of defrosting bacon, two doughnuts, her own poo, sheep poo, horse poo and cow poo, some bits of rotting rabbit that she found in the field, the edge of two rugs, the rungs of all the kitchen stools, any amount of packaging and milk cartons (nicked from the recycling) and a mars bar - that last one necessitated a trip to the vet because chocolate can be poisonous to dogs, and he had to make her sick - which cost us £30 - a jolly expensive mars bar!!
We chose a chocolate lab, because dh has been told that they have the best temperaments of all the labs - this was certainly the case with the three labs, one golden, one black and one chocolate, that they had during his childhood. Ours is affectionate, naughty sometimes (dh is never allowed to keep his socks on - she nicks them and puts them in her bed), funny and clever. She used to take herself out of the cat flap to do her business in the garden when she was little enough to fit through it, and now, when she needs or wants to go out, she rattles at the cat flap to tell us.
They have the softest, silkiest ears imaginable.
Your kids may well be very keen now, but they will not be cleaning up the wee and poo in the house (though mine will do poo patrol round the garden and collect up her offerings), and whilst they will love playing with the pup when it arrives, this will wear off, and they will find all sorts of excuses not to take the dog for walks, especially when it is wet and/or cold.
We love our lab and wouldn't be without her - currently she is asleep on the couch, wearing a specially-bought t-shirt to keep the bandage on her spaying scar clean and to keep her away from the stitches!