Clean as far as noise goes but not a good example. Looks to be a well lit room and someone could pull that off with a D80.
Did you look at the exif data on that photo? 1/25 second at 5.6 with the kit lens. The only way this photo was going to be good handheld without flash was at 6400. The room doesn't seem that well lit to me. The D80 can do ISO6400 and maintain that kind of colour saturation?
You might get lucky at 1/12 second handheld, but the ISO is still at 3200. Getting to 1600 requires 1/6 second. I have read numerous times the D80 is only good for 800 ISO. Now you are down to 1/3 second. Handheld with a moving subject? I don't get that lucky. That's why I have a D7000.
You could go the other way and attach a faster lens to a D80. Let's say a 2.8 lens which would allow ISO800 at 1/12 second. I noticed the baby's ears are already out of focus at F5.6. Now you are changing the image again by reducing the depth of field.
My point is the D80 could have gotten a shot, but it wouldn't have been THAT shot.
I think it's impressive, especially for a low-budget/consumer class DX body. It makes you think what Nikon has in store for the D4/D800/D400 series.
Don't know if I'd call the 5100 "low budget" since the difference in price between the 5100 & 7000 is $300 USD.....However, it's interesting to note that the D90 now retails for the same price as the 5100....