Duke sleeps in his crate at night, and he loves it! I have a faux fur lined snuggle sack on top of his crate pad, and he loves to snuggle in there all night long. He looks pretty darn adorable peeking out of his little snuggle sack too.
In fact, Duke loves his crate so much, that in the morning when I let him out to go potty, he usually runs back upstairs to snuggle for a while longer!