It depends doesn't it? I think its all very well and good to say "absolutely not before 3" or whatever, but if you're in a position where you need to go back to work and need childcare options, you don't have much choice! You can choose a nanny, a childminder or a nursery. Thats it. And there are pro's and con's of each. Unfortunately, there is no right or wrong answer and generalisations don't help. If you find a good nursery / childminder / nanny, that suits your child, then thats worth its weight in gold.
Having said that, I was lucky in that my mum stepped in to have my first children (twins) for the 3 days I worked until they were 2. At that point, they were ready for nursery, could talk, hold their own if necessary (i.e. if other children snatched toys etc). They were ready for more interaction with children, wanted / needed lots of entertaining that I felt a nursery could offer. I wanted them to be with other children (which ruled out a nanny ? it was probably going to be too expensive anyway) and for me personally, I didn't like the idea of a childminder ? just my opinion but if there is one childminder with 3 or 4 children say who are a mixture of ages including a young baby (which would take up lots of the childminder's attention) and say an older one at school (so the children all have to do the school run twice a day), I didn't think a childminder could give my children the attention and age appropriate activities / socialisation that they needed.
I didn't have the same options when I had to return to work after maternity leave for my 3rd child when she was 12 months ? but we've moved areas by then and found an absolutely brilliant nursery where the baby unit was completely separate to the rest of the nursery ? 1:2 staff ratio, dedicated sleep area with each baby having its own cot.
So its a question of seeing what you can arrange locally ? if there are nurseries that are recommended / friends have used them, go and visit. Similarly if there are childminders / nannies at the baby groups you go to that seem to have a great bond with the children they look after, speak to them. Its about finding something that you're happy with. So be open minded about it ? don't rule anything in or out until you know what options you have.
Good luck!