Looking through what's on sale, I realize that I am pretty happy with my kit as is. I have the 18-55 for walk around, "wide" angle etc. (not being a big wide angle shooter, I think 18mm is fine for me). I have the 60mm for macro and the 50-230 for longer reach. No way am I carrying that heavy 100-400. I was going to get the 80mm when it came out but I'm not liking that swirly bokeh when it's used for portraits. I guess if I have to pick something that I need it would be a fast prime but I can't see spending for anything in the 18-55 range. Maybe the 90mm but I would definitely be buying that used...
I am tempted to pick up a back up body like a xt10 or xt1 but since I'm not a pro there really is no great need for that and it would basically end up with Princess then I would be constantly having to chase her down to get my lenses back!