Newnes is on our to do list but only has drop toilets, no showers.
Lake Lyall at Lithgow is also on our to do list in the warmer months, went for a drive there last month for a look see and it was quite good, amenities blocks were pretty good with hot showers(20c I think for 3 mins), fireplaces, powered/unpowered sites, kiosk. The water level is getting pretty low but the view from the top camping areas are just beautiful. Also heaps of bushland for the kids to wander around in and explore.
Here is a thread on the Blue Mountains which has the above places mentioned plus a couple of others, also has photos. http://forum.camping.com.au/viewtopic.php?f=64&t=5032&start=0&hilit=lake+lyell
You could also try the South Coast as I am sure there is some really nice spots down there. Just do a search of this forum and you will get plenty of info.