I am a bit confused in choosing a new lens, I've been googling about the 50 mm lens all day. This is the result (hopefully the info might help you, and this is for Nikon user).

FIRST, why 50 mm lens?
Because 50mm "normal" lens is the first lens most people acquired with their cameras.
This lens is called a "normal" or "standard" lens because the way it renders perspective closely matches that of the human eye. Also the lens usually have a smooth bokeh. But in other hand The 50mm lens is just that: 50mm. A prime lens does not zoom in or out, "You must get closer to or further away from your subject to change your framing with a prime lens".

SECOND, there is the big difference between AFD and AFS.
AFD will be cheaper since it has no internal focusing.
mean the lens is equipped with a silent wave motor for fast autofocus operation.
Nikon lenses that are not AFS are focused by a motor in the camera body.

THIRD, this is a tough decision to make because both lens are 2 equally good options.

Okay the first one is Nikon Lens AF-S 50mm F1.4 G
The lens is expensive around IDR 4.500.000 but recommended by most photographer forum.

(I found this on Amazon.com's review by Sidarta Tanu
Pros :
  1. AF-S AF-S AF-S (very fast focus, internal focus, and very silent)
  2. M/A mode (manual focus override available on autofocus mode)
  3. Very fast lens (f/1.4) and sharp pictures
Cons :
  1. Being a G lens (no aperture ring available), this lens will not work on manual focus camera where you need to set the aperture from the lens)
  2. Price is a bit on the high range for a prime lens
  3. No VR. As VR will be useful for taking handheld shots on low light (especially if the object is somewhat static or if the photographer doesn't have steady hands when taking photograph)
The other one is Nikon Lens AF 50mm F1.8 D
A whole lot cheaper only IDR 1.400.000 but I have to switch to manual focus,
because it is not an AFS type.

Pros :
  1. Very fast (f/1.8)
  2. Very sharp pictures (especially when stopped down to f/2.2, f/2.5 or more.)
  3. Fast autofocus
  4. Inexpensive
Cons :
  1. Autofocus issue on some situations
  2. Autofocus is not the most silent but very reasonable
  3. Plasticy build
  4. Autofocus does not work with D40, D40x, D60 and D5000. The newer 50mm f/1.4G AF-S lens or 35mm f/1.8G AF-S lens will autofocus with those cameras.

Both lenses :

  1. Being prime lens, you need to move your feet a lot to adjust/compose
  2. Great for sport/action photography, indoor, low light situation and portrait
  3. Bokeh is almost as good as many expensive Nikon tele-lens
  4. Perfect for wedding photography (or low light with no-flash event). However, also check out the following lens for wedding photography (17-35mm f/2.8, 24-70 f/2.8, 17-55mm f/2.8, 28-70mm f/2.8 or the other two 50mm nikon prime lenses).

Now I had no idea, which one should I choose.
Number 1 is too expensive for my first lens but the result is great and can use autofocus.
Number 2 is cheap but not as good as number 1.

Check out these great shots here.