I belonged to the Gold's Gym in Long Branch, NJ for a couple of years, and it got me into great shape while leaving me feeling pampered and very comfortable with my surroundings.  The child care was a big seller - responsible caregivers and a room with three computer terminals and a large-screen TV.  You can dial up the child-care room on a special channel while you're working out on the machines and see what your kids are up to if you like.

Most of the people there are incredibly fit (and more fit than me), but I never felt uncomfortable or unwelcome.  In fact, I found more "gentle" classes...