I started back in 1987 with an EOS 620 and I slowly gathered some lenses:
50mm 1.8 (version 1)
50mm 1.4 (that was stolen)
100mm f/2.8 Macro (the first, non-USM, non-L version)
300mm f/4L non-IS
TS-E 24mm version II
Zeiss 21mm f2.8 ZE
These lenses have been used for prints, slides and b/w.
When I was involved with b/w and was printing photos with sizes between A4 and A3
I remember that I was disappointed with the performance of my 28-70/2.8L
So I switched to the primes (by that time I used mainly 24mm, 28mm, 50mm) and I was very satisfied.
It is inevitable to not use all the lenses all the time.
Some time in the past I got the 16-35/f2.8 L (version 1), the 24-70mm f/2.8 L and the 70-200mm f/2.8 L (non-IS) zooms
which I liked a lot (Unfortunatelly the last 2 were stolen too) so I had stopped using many fixed lenses.
Right now some prime lenses are not being used but some prove very useful:
My 100mm Macro is sharp.
It is very interesting that this supposedly "lowly" non-USM, non-L slow focusing lens
excelled in photographing a flower
in the same distance where my 70-200 f/4L IS failed miserably to focus
(In some photos it looked like it was back-focusing and in some everything was not focused)
In addition you do not need a hood since the first element is very recessed.
Same for my trusty 300mm. It is very sharp wide open.
I have photographed many sunsets, landscapes in general and a total eclipse. (with an EF2x II teleconverter)
Also it has been used at wetlands with a 5DmkII successfully.
This lens stays no matter it has no IS.
I admit that I have questions about the 85mm (on the other hand I have not used it a lot)
I love the 135mm wide open ( very impressive between 2.0 and 2.8 )
The 21mm Zeiss is sharp edge to edge a feature I missed on my 16-35mm zoom.
Also it is very nice for Astrophotography since the infinite position is indeed ... infinite.
Finally with the TS-E 24mm II no more converging verticals in pictures of buildings and ancient temples.
Right now I try hardly not to think TS-E 17mm since it seems that 24mm is not wide enough