Photographers often get very excited about 50mm lenses.
So why the fuss about the Nikon 50mm 1.8 D AF?
Firstly, the 50mm 1.8 is a good introduction into the world of "prime" i.e. not zoom, lenses. Primes lenses are valued because there is no optical compromise made while trying to design a lens which will work at say, 16mm as well as at 85mm.
Historically prime lenses like the 50mm have been sharper and superior to zoom lenses, and come at a higher cost - especially if you have to buy two or three to get the focal flexibility a single zoom lens would cover.
But unlike many primes, the 50mm is very affordable. It's also very small and light, tucking neatly into a camera bag or pocket, meaning it's not a hassle to lug around and will always be handy.
It's light because it's mainly made from plastic, although the important thing, the mount, is hard wearing metal and the plastic is tough and feels sturdy. Plus, with a lens this small, materials are of slightly less importance.
It's size means it's very low-profile when mounted on the camera, making it a little less frightening than a big zoom lens.
Photographers also like as much light let into the camera as possible an again the 50mm gives a cheap entry into the world of "fast" lenses. The lens is certainly fast and sharp, although the wide apertures you'll be able to enjoy also sees the pay off of razor thing depth of field, so keeping focus sharp and on the right point is a challenge.
Photographers also rated 50mm lenses because on old 35mm cameras they gave a field of view about the same as the human eye. Here's where the 50mm on a digital changes things, with the crop factor of most (not full-frame) Nikons, the lens will really be a 75=88mm making it ideal as a portrait lens, but perhaps disappointing to old film photographers coming to digital.
Distortion is well controlled, as you'd expect from a prime. Sharpness, again, is excellent and it's been suggested even better than the much more expensive 1.4 D AF.
Autofocus is blisteringly fast, but noisy and perhaps because of the speed of focus, can be a bit too "torquey" and you sometimes feel the camera body shift slightly in your hand as the lens snaps into focus.
Colour rendition can surprise - and you'll occasionally get very different colours than you do from other lenses during the same shoot. This calls for good white balance discipline and perhaps just paying attention while photoshopping.
It's a shame the price of this lens has crept upwards recently, but even so, it's still a bargain (and just shows those who bought a few years ago got an even better bargain). You won't find a better or cheaper way of getting a quality Nikon prime lens which performs at this level. It should be in everyone's bag!