I'll start .....
At the moment (ds is 2.8):
Nursery £125/week
Clothes/toys £5 week on each (mostly not new, and ds isn't old enough yet to distinguish between lots of toys from car boot sales at a few pence each, and a few new ones at shop prices).
Birthday/Christmas probably about £200 total, so £4/week on average
Annual pass to local farm park/soft play area £50/year, so £1/week
Other activities/swimming, etc £5/week
Food/drink (above what we spend on ourselves): £20/week (most meals during the week are at nursery)
Eating out: £3/week
Nappies/wipes: £3/week
Holidays/Days out: £20/week (including entrance costs for us to places we wouldn't go without him - it's only so high because we take him to Canada each year and pay airfares)
Savings: £20/week
Other (skis, redecorating his room, birthday party, birthday cards/presents for friends, etc): £5/week
Total: £216/week for 1 child.
More than half of that is nursery fees, which hardly figure in the original article but I'm sure are an equally significant factor for anyone with pre-school children. But then nor do they include savings and holidays, and I'd bet the example families have those too. Yet they include "food for the family" - surely some of that would be bought for the adults even if they didn't have the children, so it's hardly realistic to include it in the cost of having children. And for them to take the current cost per child, per week and just multiply that by the number of weeks in 21 years is way, way, too simplistic. By that reckoning ds is going to cost me over £236,000!
Actually the original survery they've done this article on the back of is a bit more realistic in recognising that expenditure changes at different stages, but it still nothing like our situation (why do average childcare costs/year go up when the child starts school, and pre-school children get pocket money, but 5-11's don't?)
We're definately way over their estimates for the 1-5 group, but will hopefully be under for 5-11 (as have no expectation of paying over £7k/year for a nanny).
There's quite a good take on this in today's Telegraph