My modular synthesizer.
I love it and I’ve poured far to much money into it for something that doesn’t come close to the power of making music in a DAW. But I do love it, and it can do some cool stuff that I’ve not been able to reproduce in a DAW - like random triggers and probability. It’s also nice to get away from my computer.
The initial investment can be steep, but if you stick with buying second hand modules and look for deals, it’s easier. Plus the spending only really goes down over time, at a certain point you realize you have all the modules you need, and you find yourself only buying a module or 2 a year.
Also modular stuff holds its value really well. If you buy second hand, you can basically sell a piece of gear for what you paid for it, so if you get something you don’t love, you don’t lose much.
Having said that, cardinal and vcv rack is great, vcv rack is where I started and I used that for a few years before taking the plunge