Well I know the right answer... but I have furry kids... so I'll give you the right answer and the honest answer.
The right answer is to keep the dog crated at night. Once trained, the animal will enjoy his own space and the crating allows for seemless transitions when boarding, having the animal overnight in a hotel (most require crating), or even pet sitting. Greekman is right, keeping the animal crated is best for the animal.
That being said, however, my dogs sleep with me at night. I know, I know. Like another poster said, I'm gone all day at work, often volunteer my time, and/or am running around like a chicken with my head cut off with my kids, friends, family, etc after work so I feel bad that the dogs are crated all day... so I just can't crate them at night too. They probably wouldn't mind.. but my human nature kicks in. The Chi sleeps under the covers in either my bed or my son's, and the Westie sleeps at the foot of my bed.
One issue I have is that when they are ready to wake up, they do their morning shake to get their wiggles out... and those damn ID tags are NOISY. lol. There's no sleeping through that. :)
I just got back from vacation, and for the week before vacation, I put the dogs in their respective crates for the evening so they would be acclimated to their crates for night. My dog sitter said that watching them was the easiest thing in the world because they both crated on command and without complaint. I don't know that I believe the "once they're on the bed you can't get them in a crate" mindset. Mine had no problem with it.
Good luck!