I am a pretty odd duck. I wear sweats around the house but won't wear them outside for anything other then taking the dog out for potty. I won't wear shorts outside either.
Once I fall asleep - it is over! When DH was in Iraq, I slept a lot of nights in my sweats and a large t-shirt ontop of the covers.
If I am crawling into bed for a good nights sleep next to my man - something on the bottom half of me (anything from just plain ole' undies to boxers)and a really big t-shirt