We purchased the largest bed for our 10-month old Standard Poodle.  She loves it and stretches out and already it is a perfect size for her.  As she grows a bit more it will be just fine.  I love that she uses the edges for a pillow and that it can be laundered.  The price was right and we can't be more pleased...we bought TWO...one for her bedtime arrangement and one for naps wherever we are.