This is another item that is a big hit with my four cats, and I've had to buy two more just so there aren't arguments over who gets in it next.  This is a pretty good size, and all my cats enjoy the fit, from my tiny 5-lb princess to the 20-lb bruiser.  I have put one over a heating vent, making it a "cat magnet" during chilly months.  If you have multiple cats, buy more than one!  

Pros: Good Size, Comfortable, Easy to Clean
Cons: Too Popular with the felines!