Pssst, it is in Cambridgeshire now. There is no Huntingdonshire anymore.
Like I said in the other post, it is going to depend on where you plan to work. If you need to depend on the A14 it could be very messy, but the guided bus should be open in late summer. It should have opened in April though.
As for the three, according to my not very helpful workmates, St. Ives has a tendency to flood, but is very pretty. Huntingdon is a bigger city and can have some very rough spots and no one seemed to know much about Godmanchester other than they all seemed to think it is/or will be soon swallowed up by Huntingdon.
Sorry, no one I know has any kids. They all have less to do in terms of museums and the such due to the University, but if you are working in Hunt. then commute from Cambridge is a killer.