thermosflask - I can appreciate your views, and have read a number of articles about attachment theory (degree in child psychology here although I haven't used it in a few years now) - however I think your focus is a little narrow.
Attachment theory basically says that ANY adult as long as they are giving the child 'appropriate attention and affection' (and that definition is hazy at best (does a mother with three children give all of them the necessary amounts, as an example). It doesn't NEED to be the mother (or the father).
Additionally, going back to work after the children are in school/left home/whatever ISN'T a choice for many people - some jobs just can't be kept open indefinitely (or even for 9 months, whatever the legislation says in the UK currently) and the family needs the mother's income.
It's not as black and white as "if you go back to work and leave your child with someone else you don't care about their development". Many working mums (and I'm one!) feel guilty about leaving, but because I spent the time finding someone to look after my DS that I trust - I can feel 'better' about not being the one at home with him.
Additionally, yes of course I derive a lot of personal satisfaction from my job (and gosh the chance for adult conversation and the opportunity to go to the toilet by myself!) so I would recognise that it's a benefit for me (apart from the financial one) - but I believe that separation which work creates allows me to be a better mother, more attentive to my child's needs, when I am at home - because I have the chance to think about how much I want to spend time with him (and that I don't just focus on the chore mountain that overtakes my thoughts when I'm at home when my nanny is on holiday or I'm at the weekend).
Your opinions are, of course, your own - but I think if you look honestly at your comments I believe you were trying to 'lead from truth' (or what you perceive to be the truth) but not to 'lead from love'. And by that I mean that you were more concerned about pushing your own judgements on someone else (or trying to make them feel guilty/bad about their choices) - than trying to help them with their issues.
Trust me, most working mums I know torture themselves about whether it's the right thing to do for their child if they go back to work or not - so it's never an easy decision, or at least it hasn't been for any of my friends/colleagues.
If you are financially able to stay at home with your children, and that fulfills you - then that's great. But passing judgement on other people because they are not able to do so, especially when they are expressing concern about it being right for them, isn't terribly fair.
kcj748 - I hope you have managed to take something positive from this post, which is that a lot of people support you in your need to go back to work, that leaving your child at 4/5 months is possible - and I hope that you find a good childminder (or maybe a recently qualified nanny who will work cheaply to build up the experience they need?) that will allow you to feel confident about leaving your precious child with them. Good luck.