A friend was against the kids getting an allowance, but her husband thought the kids should get one.
So the kids do the normal stuff (cleaning up after themselves, dishes away, setting the table, etc), but then they have "Money Chores". She has a board on the fridge with different things and what they will get for them.
$2 to weed the garden/$3 to clean up after the dog/$4 to do laundry/etc. If the kids do that stuff, they initial the board and get money at the end of the week.
I don't have kids, but seemed like a good compromise between stuff you need to do to help out in your family, and things to do to earn some money.