I have the 15, 21 (latest addition), 25, 28/1.9, 35/1.7, 50/1.5, 75, and 90.
I had the 35/2.5 C but sold it. Never used it. I'm considering selling the 90 as I never use that, too. The 28 Ultron gets the most usage nowadays, followed by the 50 Nokton.