Small (but sturdy) to medium is my preference. I like having a dog that you can easily take just about anywhere. I travel a lot and having to be packed into my Jeep with a large to ex-large dog would probably not be a very fun ride. :-D

Also, I find that anything medium and below is not able to push me off the bed at night like a certain dog I know of can! [cough]SKYLAR![/cough]