What is the one lens you would never sell?

It's easy to grow attached to lenses, especially great ones. With all of the options available to us, what is the one lens in your bag that you would never sell? Why?

I'll start. I would never, EVER sell my Sigma 400mm 5.6 APO HSM Macro. Why? because it rocks. No, seriously, it rocks. It does 1:3 macro. And even though I can only use it wide open, it's TACK sharp. I also wouldn't sell it because the copy I found was only used for like 40 shots and in brand new condition.

Canon 135L

50L

35L

never sell? my 18-55 non IS kit lens...
i'd never sell cuz it's worth nothing

i'll give it away tho... lol

70-200 f/4 IS. Awesome lens.

70-200mm f/4L IS. When I recently took the plunge into wedding photography, instead of sell and get the f/2.8 version for it's extra stop, I opted to keep my f/4 because of its compact size and excellent IQ, and buy a Canon 85mm f/1.8 for low light. Seems to be working for me so far.

It is the only lens in my bag that blows me away almost every time.

24L II

300 2.8L IS

85l

85L, I want to be buried with it.

Any lens that I don't have, I will never sell
New lens are always better (look at 70-200 M2)so that is nothing I will never sell

This is a tough one for me because to me, a lens is a tool.

If there are better tools out there, I trade.

That said, the two lenses that really earn their keep right now are (1) my Canon 24-105 and (2) my Sigma 50-500 OS.

85L

My nifty-fifty is never going to be up for sale! I wanted to sell it a few times actually, but each time found out that $80 really will not change anything, and will not put me any closer to 50L. This is why nifty is a keeper!
But I got a 2nd copy along with a body that is up for sale now