Now, I find it extraordinary and refreshing that hardly anyone got down to some serious gear talk and recommendations yet
I'm not a Fuji shooter, so I guess I would have to approach this from a different angle.
Anyhow, while I'm basically with
@donlaw on why I sometimes (well, quite often) go with new gear instead of old is curiosity, I've found recently that hitting the spot is even more satisfying. So I fully understand where
@Bobby Tingle is coming from.
The way I see it, most of the stuff that can be done with a 50-140mm (at least when it comes to portraiture and people stuff) can be done with the 90mm f/2. The 16mm is obviously the right companion for that lens. If, however, I knew that the 50-140mm would help pay some bills and make me enough money to get the two primes later, that's what I'd go for first. Workhorses are always welcome - I keep mine ready all the time.
However, in my experience as a hobbyist who isn't into wildlife and sports, the longer and heavier the lens, the less I use it (superzooms excepted - that's because I use the long end when I have it available without having to swap lenses). Hence, the lens I'd really love having would be the 90mm f/2, not the 50-140mm. The 90mm is a strong portrait lens as well as a capable macro tool, it's weather-sealed and just portable enough to be taken out regularily. The 50-140mm is bigger and heavier; it certainly precludes small bags.
My rule of thumb is: If you need it, get it - but if you're not sure, don't get anything that doesn't fit into an ONA Bowery alongside the camera ...
M.