A lens reduction question.

I think I know the answer to this question, but need some reinforcement.

Most of my shots with the DSLR have been with a 70-200 f4 IS lens. Other non-tele needs have been going to my super-zoom or pocket camera......both very good quality, and tops in their catagories.

I also have a fisheye lens, a 50 1.4 lens, and a 17-50 2.8 lens. I like the fisheye as a fun lens. And....it can double as a super wide angle if I'm able to watch out for the severe distortion, or can remedy that distortion in post. So between the 17-50mm and 50mm lenses, which would you keep, and which would you bid good bye? I have not used either one all that much. So can't go back and check to see which has had more work. I'm guessing you'll say keep the zoom; as it covers more range and has a reasonable fast aperture. Yet the 50mm lens would be even better for lower light; one thing that neither the other zoom nor my non-DSLRs can deal with very well.