It really depends on how I feel.
In this weather I always walk around the house in boxers and t-shirt, so when it comes to going to bed, I just flop onto the matress and crash out.
In the winter, I sleep naked more, because it's nice getting warm under the covers. But I've had people walk in my room and get a face full of naked Kir when I've accidently tossed by duvet into a free-for-all-viewing position.
Sometimes I wear PJ's, sometimes I wear just boxers.
It just really depends how I feel at the time! I enjoy it any way possible!