I currently have a Nikon F80 with a SIGMA 28-105mm F2.8-4 D Aspherical, SIGMA 70 - 300mm F4-5.6 DL macro and a NIKON 50mm F1.8 AF-D. All the equipment are almost brandnew, about 4weeks old. However, I almost never use my Nikon 50mm. My workhorse lense is the SIGMA 28-105mm , and I seldom need a F1.8 lense. The Nikon is supposedly a better lense in terms of optics, but the SIGMA is just as good, only slower. I dont know, maybe I've had these equipment for only 4 weeks, but the Nikon always sits in my camera bag. I do use it once in a while, just to justify its prescence, but the SIGMA 28-105 always end up on the camera body. Its just so much more convenient to be able to frame my pictures with the touch of the zoom ring.
I've tried using the 50mm for indoor shots due to low lighting and the fact that I rely solely on my built in speedlight, but it can be challenging with its very very shallow depth of field. Family birthday party shots tend to have a single person rendered sharp, but the rest... sadly blurred out. Even taking potraits for 2 people, usually 1 person would be a little out of focus. I dont know if I should keep it, or sell it. Its indeed a very sharp lense with vibrant colours, and very fast indeed. But for an amateur like me, who do outdoor, nature, people, cars and sometimes indoor shots, should I keep it ? or is my sigma enough .... ? Give me some good reasons why a 50mm F1.4 or F1.8 is almost always owned by avid photographers ?