I've got most everything I "need" at this point in my life, with the room and $$ I've got. I want to get into other areas like metal fabrication, but know that even if I bought nothing but used equipment it would be a substantial investment in time and money, both of which are a premium right now.
But what really comes to mind would be the little yet expensive/time consuming things that would make my life easier. For example. I bought a cheap CM 113.xxxx table saw, fixed it up really nice with a Biesemeyer fence and made a nice rolling stand. But I don't have a lot of the things like dust collection, feather boards, and other accessories that would make setup and use much easier and safer.
I have a drill press, but don't have a fence system setup and wish I had a storage cabinet close by for all the accessories. Also wish I had dust collection for it.
So for me, it just comes down to the finishing touches on a lot of projects I have already started.