The Nikon Nikkor 50mm 1.8D AF Lens is one that was just recently added to my collection. I previously had purchased a Nikkor 18-135mm and a Nikkor 70-300mm lens, so I had my zoom lenses covered, and I wanted something that would be better in a low-light situation, or to use indoors. This is definitely the right choice- and the best part is, it doesn't break your budget!!
The 50mm lens is a prime lens, meaning that it doesn't zoom in and out like the telephoto lenses do- it is also a wide-angle lens, which means you will capture a wider area on your photos. The fact that I had only been using telephoto lenses before trying the 50mm out, it took a little getting used to, but I have really grown to love it. I love the fact that this lens is autofocus, but it can also be used manually as well, so it is really convenient for lower light, where the lens tends to "search" a bit for the focus.
I have had good success with using this lens in low light situations- the 1.8 focal length is really great for dark areas with bright lights, such as concerts and shows on a stage. The photos were pretty clear, and I suspect the ones that weren't were only due to photographer error, not the lens. This lens performed much better under these conditions than my other 2 previously mentioned lenses.
One of the best features here in my opinion is the price- only around $120 dollars! Definitely a good one to have, especially if you are just starting out. Another thing I love about it is the size- nice and small, and very lightweight (only 0.34 lb), so it is easy to carry all day on your camera, and super easy to travel with.
I would definitely recommend trying this lens out- it is a winner in my book!