I use here and one another parenting site. Both have lovely feels to them, but are different in their own ways too.
I used to use Baby World - but I don't like their new format, and the general discussions got very odd at times. I very occasionally revisit my antenatal club there but it is not used much nowadays - only near Christmas/Birthday times.
I also used Raising Kids for a while - but it seems a bit too arguementative for my liking!