Ok, I don't pretend to know much about this subject and am very open to being educated so please don't jump on me. I'll also freely declare that I'm pretty much on the left, politics-wise.
But (and putting disability entirely to one side for a moment), here's the thing - I'm a single mum with one DS, I rent out part of my house to minimise costs, I moved countries when my marriage broke down in order to get a higher paying job (a 30 hour flight from my nearest family), I have insurance policies coming out of my ears (income protection, life insurance, mortgage protection, you name it) to minimise the risk, as far as I possibly can, of ever having to rely on the State. I'd love to have another child but I can't afford it so DS will be an only child.
I do believe wholeheartedly that there should be a safety net for when the going gets tough. That could easily be me one day. But, the reality is that there are families out there where 2nd, 3rd and 4th children are born when the parent or parents are already receiving benefits (not sure about UK figures but here in NZ it's something like 20% of children born are to beneficiaries). I just don't see that this can be right either. On that basis, a cap does seem - at face value - like a reasonable move, although ideally I'd like to see it accompanied by more investment in education and uni fees for disadvantaged children to enable and encourage them to move out of poverty for themselves. I also don't see that people should be paid a benefit to stay in the area of their choice when there may be cheaper accommodation elsewhere.
Oh, and - to RobF - the trickledown theory of wealth creation is well and truly dead. Wealthy bankers and the like don't add to the economy in the way they like to believe - especially when so many do so much to avoid paying their taxes. Phillip Green is a classic example, sadly. On the whole I reckon more of us would be better off (or at least feel better off - which actually is the real battle) with an economy that encouraged an equitable spread of wealth.