FWIW, my cat is very happy that I bought her an electrically warmed pet bed.
If your place gets cool in the winter and you've got a heat-seeking cat
(some cats are and some aren't), you might want one of these. (You can tell
a heat-seeking cat because he's a seasonal lap cat; he'll ignore your lap
when he's warm, but suddenly become friendly when the weather cools off.)
This one draws about 11 watts, and the result is a subtle but pleasing
warmth. Also, since it's low voltage, there's no electrical hazard.

http://www.countrysidevetsupply.com/prod.itml/icOid/325

(No, I don't sell these; I bought one for my cat and she likes it, so I
thought the info might be useful.)