Having tried most of the Fuji lenses (except the really, really expensive 200mm and a couple of the new ones) there are a few that would make my "never get rid of" list.
16mm f1.4 - I know, I did let this go, but wish I hadn't. Such a versatile lens and so sharp.
100-400 - I shoot a lot of wildlife (or at least try to) and this is a cracking piece of kit. Also does the job for motorsport too.
10-24 f4 - Since letting the 16mm go, almost all of my landscape stuff is done on this, and I love it.
35mm f1.4 - Probably the lens I enjoy using most, it's sharpness is unbelievable at times and the way it renders wide open is just joyful.
There's a couple that I don't have, (such as the 16 f1.4) but if there was one more I could add it would be the 23 f1.4. I often use the 10-24 as a walkabout lens, but tend to find myself shooting at the long end most of the time when used like this, so the 23 would be almost glued to at least one body.