I am thinking of finishing my basement. Nothing fancy, just a play area for the kids. I have pretty low ceilings with pipes running on the perimeters for my heating system that are even lower. I am going to put a drop ceiling and box out where the pipes are.
The basement stays pretty cool all year round. It is a little humid though.
1- Can I carpet right over the concrete slab? It never gets wet at all.
2- Will it be necessary to insulate the exterior stick framed walls?
Yes, you can carpet right over the slab. As long as you're sure you're not getting any moisture intrusion, you'll be ok with carpet. There are types of carpet that are better for this use, and hopefully someone that knows something about carpet will chime in.
I definately recommend that you install or use a dehumidifier to deal with the humidity though.
It is always a good idea to insulate the basement walls. A good vapor barrier installation is important too.