I saw mine last week. I was terified that she would be inspecting the house and our parental abilities and spent the whole weekend before cleaning the house from top to bottom...I really over did it. She came in, sat in the living room and that was it. She didn't even look at our kitchen - I was, in a way, a bit dissapointed as the oven was very shiney!
They like to visit you before the birth to discuss loadsa stuff with you (things like SIDS, whether you plan on breastfeeding etc). She will be your support after the baby is born (like your midwife is to you now) so it is important that you meet her beforehand. Mine gave me so many leaflets that I still havn't had the chance to read through them all.
My advice: don't worry - she is not there to evaluate you. Oh, and don't worry too much if you can't quite get that cobweb in the corner of the room. Lol