Any ideas on a good family campground in Maine?

I am trying to decide on a good family campground in the mountains, preferably on one of the many lakes. I would like to know some of the places you all have been and what you thought of the experience. I have received a bunch of literature on several different campgrounds and I have also done a good bit of research on the mountain lake areas, but nothing beats personal experience in my opinion. My family and I love to fish, hike, possibly some whitewater stuff and horseback riding.
A primitive site would be ok, but a site with at least electric would be ideal.

Thanks for any info you can give.