First, regarding the dismissive comments about state childcare, the council nurseries in my area are great, and offer high quality paid for childcare at a lower rate than the private nurseries, though it's still a lot of money.
As for the option of free childcare or more subsidised childcare, as well as wrap around care, would give working parents more options - I worked full time after having children until I was made redundant (nearly 3 years after returning to work from maternity leave the 2nd time) and am now using part time childcare while I try to start freelancing from home. My parents are actually paying most of the cost of this at the moment (they're not together but are both contributing), and my dad helps us out a bit with other extras (I'm very lucky, I know). DS2 is at the local school nursery class and that's free but it's just every morning (15 hours as 3 hours a day), and so that doesn't actually reduce the costs of using a childminder. Next year when DS2 starts school, I will probably try to find work outside the home - having to cover costs of nearly £300 a week before I bring anything home won't make sense for temping, it barely made sense for a permanent job but I stayed because it would have got easier if I'd remained in employment, from September 2013.
Also, if childcare costs were free or even considerably reduced, part time work to spend more time with the children would be easier, and that could offer more flexibility.
I'm quite annoyed that those of you who have the choice to be SAHMs want to deny choices to those of us who can't afford or don't want to be at home full time. Because that's how I interpret a lot of the most vocal contributors to this thread.
I'm also annoyed by people who see such proposals as an attack on money no object childcare. I'm lucky to have been able to find a childminder whose rates were only about 40% of my take home pay (for one child) when I first went back to work, and that she turned out to be an excellent choice as well as being more affordable than any nursery. Council nurseries at that point would have been 50%, private nurseries would have been 75-100+%. There are a lot of not really by choice SAHMs in this area.
Finally, if you're concerned about quality then I think the Tories' proposals put forward by the likes of Elizabeth Truss are REALLY scary - deregulate CMs and allow them to look after more children. There are reasons for the ratios as they are at present.