I've managed to keep it under the radar with simple distraction techniques. I've sold my soul on the last deal however. Much of my cost lately has been towards my brewery area in general. Shelving, work benches, drying racks etc have really nibbled away at the $'s. In desperation to finish my master plan, I mistakenly said I would invest = dollars/time into moving her out of the basement entirely. This really just entails me moving our laundry room upstairs.
In the end it means she very well might go months without entering the brewery, at the onslaught it means I have to split my time working on projects. One being the very nasty project of relocating water, power, gas, and drainage to new part of the house. Toss in some demo, new flooring for the destination, and countless other aspects of something I really wish I would have never mentioned, and I'm coming out on the bad end of this stick.
Anyway, back to the original question...
I would look for glaring holes in my current system, grain mill, CF or Plate chiller, additional carboys, etc. However, I assume you have the basics covered as you are looking for suggestions. I would start by replacing everything that causes issues with your current system. For instance, add that ball-lock to your keggle, or replace the braided mesh with a bazoo T. Next I would start looking at upgrades like SS racking canes, and silicone hoses. Lastly I'd check for some luxury items like pumps, con fermenters, 3 gal cornies, and picnic CO2 management.
Good luck, let us know what you decided on!