We are in the rare position of having our son in a private nursery on a military base. Because they don't have to pay rent and electricity or grounds' repairs,they employ a full time cook and cleaner (quick mopping/toilet explosions are taken care of by a member of staff), and they have a independent sports' school come in every week too.
They go about in their little 'key worker' groups taking turns on different activities; singing, counting/rhyming games, painting, role play, manner and speech rhythms (DS says please, thankyou, you're welcome, bless you, please may I have, how do you do, my name is X, what is your name? etc. It's like a little social interactions class). They also have a high ratio of male carers, which really helps with discipline I think. It's quite regulated, although they do have 'free play' and pretty much take the nursery outside in the warm weather (we live at the bottom of Cornwall, so it gets quite hot). It is about as structured as you'd want for small kids though.
Some of the other private nurseries I've seen around here though, really just seem to have an ethos of 'do what you want, when you want' and there really seems to be a lack of direction.